TECHNICAL QUESTIONS
1. What is a virtual function?
2. Diff b/w func. overloading and func overriding.
3. What is an abstract class?
4. What are "cin" and "cout" - a function or something else?
5. If class C is derived from class B and class B is derived frm class A, define the order in which constructor and destructor would be called if an object of class C is made and explain why?
6. If class A is an abstract class in above question, define the order in which constructor and destructor would be called if an object of class C is made and explain why?
7.What is pure virtual function?
8. Give exmples of virtual func and pure virtual func in real world.
9. Give example of function overloading in real world.
10. Can two parent classes of a derived class have a member function/variable having same name?
11. What is type convertion?
12. Can int be converted into float, float to int, char to int or int to char?
13. What is multilevel and multiple inheritence?
14. Write the structure of switch statement.
15. Some questions by shuffling various case statements, bringing default to top, removing break.
16. Give output:--
int a=5;
cout<<++a<<a<<a++;
17.What is super( ); ?
18. Difference b/w c and c++ .
19. Why is java so popular?
20. What are bytecodes in java?
21. What is platform independence?
22. Write a Query to count the no. of rows in a table.
23. Write a query to find the second largest no. in a column.
24. Who is the author of C++ ?
HR QUESTIONS
1. Introduce yourself.
2. What do you know about HCL.
3. How many lamp posts are there in noida?
4. If you are given a 3 ltr and a 5 ltr jar, give two ways to measure 4 ltr water.
5. If you are given a 7 mtr rod, divide it into 7 equal parts by cutting it only 3 times.
6. Where is mount everest?
7. Can you shift mount everest from Nepal to Russia?
8. What are your plans for higher studies?
9. What are your preferred location of work?
10. Explain the project undertaken by you till date.
11. Give your idea of a good project.
12. What are your strengths and weekness?
13. If we send you to Japan, what are the problems that u'll be facing?
1) What is name of the operator in passing variable no. of arguments to function (Through some Programs)?
Ans: Ellipsis
2) Programs based on Sizeof like
sizeof("HCL") sizeof('make') etc.
3)int main(void)
{
char *ptr;
printf("%c%s",ptr[-1],ptr=&"malfunction"[4]);
}
ans: function
4)
char *ptr1, *ptr2;
char *ptr3, *ptr4;
ptr1="HCL";
ptr2="CTD"
ptr3="Tech"
ptr4="Limited"
printf("%c%s%s%c",ptr[1],ptr2,ptr3,ptr4[8]);
Ans: C CTD Tech%
5)unsigned short int I;
for i=2;i<5;i++
printf("%u",(2<
a.212 b.81632 c.000 d.none
Ans: a.212
7)
char s[]={'a','b','c','/n','c',' '}
char *p,*str,*str1;
p=&s[3];
str=p;
str1=s;
printf("%d", ++*p + ++*str1-32)
Ans:77
8)
a=10, b=11
a^=b^=a^=b++;
printf("%d%d"a,b)
a.1110 b.119 c.1111 d.None
Ans: c.1111
9) Simple programs based on #define
10) A big program was given with Structure concepts. Itz easy.
11) Another #define sum include typedef so be carefull.
#define ABC XYZ
etc.
Ans a=100
12) Some questions based on arrays and loops came.
but I remember nothing else.
FINISHED
1. Which of the following involves context switch,
(a) system call
(b) priviliged instruction
(c) floating poitnt exception
(d) all the above
(e) none of the above
Ans: (a)
2. In OST, terminal emulation is done in
(a) sessions layer
(b) application layer
(c) presentation layer
(d) transport layer
Ans: (b)
3. For a 25MHz processor , what is the time taken by the instruction which needs 3 clock cycles,
(a)120 nano secs
(b)120 micro secs
(c)75 nano secs
(d)75 micro secs
4. For 1 MB memory, the number of address lines required,
(a)11
(b)16
(c)22
(d) 24
Ans. (b)
5. Semaphore is used for
(a) synchronization
(b) dead-lock avoidence
(c) box
(d) none
Ans. (a)
6. Which holds true for the following statement
class c: public A, public B
a) 2 member in class A, B should not have same name
b) 2 member in class A, C should not have same name
c) both
d) none
Ans. (a)
7. Question related to java
8. OLE is used in
a) inter connection in unix
b) interconnection in WINDOWS
c) interconnection in WINDOWS NT
9. Convert a given HEX number to OCTAL
10. Macros and function are related in what aspect?
(a)recursion
(b)varying no of arguments
(c)hypochecking
(d)type declaration
11.Preproconia.. does not do which one of the following
(a) macro
(b) conditional compliclation
(c) in type checking
(d) including load file
Ans. (c)
12. Piggy backing is a technique for
a) Flow control
b) Sequence
c) Acknowledgement
d) retransmition
Ans. (c)
13. In signed magnitude notation what is the minimum value that can be represented with 8 bits
(a) -128
(b) -255
(c) -127
(d) 0
14. There is an employer table with key fields as employer number data
in every n'th row are needed for a simple following queries will get required results.
(a) select A employee number from employee A , where exists from employee B where A employee no. >= B
employee having (count(*) mod n)=0
(b) select employee number from employe A, employe B where A employe number>=B employ number
group by employee number having(count(*) mod n=0 )
(c) both (a) & (b)
(d) none of the above
15. Type duplicates of a row in a table customer with non uniform key field customer number you can see
a) delete from costomer where customer number exists( select distinct customer number from customer having count )
b) delete customer a where customer number in b rowid
c) delete customer a where custermor number in( select customer number from customer a, customer b )
d) none of the above
Section B
1. Given the following statement
enum day = { jan = 1 ,feb=4, april, may}
What is the value of may?
(a) 4
(b) 5
(c) 6
(d) 11
(e) None of the above
2. Find the output for the following C program
main
{int x,j,k;
j=k=6;x=2;
x=j*k;
printf("%d", x);
3. Find the output for the following C program
fn f(x)
{ if(x<=0)
return;
else f(x-1)+x;
}
4. Find the output for the following C program
i=20,k=0;
for(j=1;j<i;j=1+4*(i/j))
{k+=j<10?4:3;
}
printf("%d", k);
Ans. k=4
5. Find the output for the following C program
int i =10
main()
{int i =20,n;
for(n=0;n<=i;)
{int i=10;
i++;
}
printf("%d", i);
Ans. i=20
6. Find the output for the following C program
int x=5;
y= x&y
7.Find the output for the following C program
Y=10;
if( Y++>9 && Y++!=10 && Y++>10)
{printf("%d", Y);
else
printf("%d", Y);
}
Ans. 13
8. Find the output for the following C program
f=(x>y)?x:y
a) f points to max of x and y
b) f points to min of x and y
c)error
Ans. (a)
9. What is the sizeof(long int)
(a) 4 bytes
(b) 2 bytes
(c) compiler dependent
(d) 8 bytes
10. Which of the function operator cannot be over loaded
(a) <=
(b) ?:
(c) ==
(d) *
11. Find the output for the following C program
main()
{intx=2,y=6,z=6;
x=y==z;
printf(%d",x)
}
Aptitude
1. How many of the integers between 25 and 45 are even ?
(A)21 (B)20 (C)11 (D)10 (E)9
Ans:d)10
2. If taxi fares were Rs 1.00 for the first 1/5 mile and Rs 0.20 for each 1/5 miles thereafter. The taxi fare for
a 3-mile ride was
(A)Rs 1.56 (B)Rs 2.40 (C)RS 3.00 (D)Rs 3.80 (E)Rs 4.20
Answer :d)Rs 3.80
3. A computer routine was developed to generate two numbers (x,y) the first being a random number between 0 and 100 inclusive, and the second being less than or equal to the square root of the first. Each of the followin pair satisfies the routine EXCEPT
(A) (99.10) (B) (85.9) (C) (50.7) (D) (1.1) (E) (1.0)
Answer : A) (99.10)
4. A warehouse had a square floor with area 10,000 sq.meters. A rectangular addition was built along one entire side of the warehouse that increased the floor by one-half as much as the original floor. How many meters did the addition extend beyond the original buildings ?
(A)10 (B)20 (C)50 (D)200 (E)500
Ans: c)50
5. A digital wristwatch was set accurately at 8.30 a.m and then lost 2 seconds every 5 minutes. What time was indicated on the watch at 6.30 p.m of the same day if the watch operated continuously that time ?
(A)5:56 B)5:58 (C)6.00 (D)6.23 (E)6.26
Ans :E) 6.26
6. A 5 litre jug contains 4 litres of a salt water solution that is 15 percent salt. If 1.5 litres of the solution spills out of the jug, and the jug is then filled to capacity with water, approximately what percent of the resulting solution in the jug is salt?
(A)7.5% (B)9.5% (C) 10.5% (D)12% (E)15%
Ans :A)7.5%
7. A plane travelled K miles in the first 96 miles of flight time. If it completed the remaining 300 miles of the trip in 1 minute, what was its average speed in miles per hour for the entire trip ?
(A)
(B)
(C)
(D)
(E)
Ans :(300+k)/97 * 60
8. A merchant sells an item at a 20 percent discount. but still makes a gross profit of 20 percent of the cost.What percent of cost would be gross profit on the item have been if it had been sold without the discount?
(A)20% (B)40% (C)50% (D)60% (E)66.6%
Ansr :c) 50%
9. A millionaire bought a job lot of hats 1/4 of which were brown. The millionaire sold 2/3 of the hats including 4/5 of the brown hats. What fraction of the unsold hats were brown.
(A)1/60 (B)1/15 (C)3/20 (D)3/5 (E)3/4
Ans :c)3/20
10. How many integers n greater than and less than 100 are there such that,if the digits of n are reversed, the resulting integer is n+9 ?
(A)5 (B)6 (C)7 (D)8 (E)9
Ans :D)8
11. An investor purchased a shares of stock at a certain price.If the stock increased in price Rs 0.25 per share and the total increase for the x shares was Rs 12.50, how many shares of stock had been purchased ?
(A)25 (B)50 (C)75 (D)100 (E)125
Ans :B)50
12. At a special sale, 5 tickets can be purchased for the price of 3 tickets. If 5 tickets are purchased at the sale, the amount saved will be What percent of the original price of the 5 tickets?
(A) 20% (B) 33.3% (C) 40% (D) 60% (E) 66.6%
Ans :c)40%
13. Working independently, Tina can do a certain job in 12 hours. Working independently, Ann can do the same job in 9 hours. If Tina Works independently at the job for 8 hours and then Ann works independently, how many hours will it take Ann to complete the remainder of the jobs?
(A) 2/3 (B) 3/4 (C) 1 (D) 2 (E) 3
Ans :E)3
14. A decorator bought a bolt of d m number of red chips in any one stack ?
(A) 7 (B) 6 (C) 5 (D) 4 (E) 3
Ans :C) 5
15. A sink has 12 lits of water some quantity of water is taken out. if the remainng water is 6 litres less then the
water taken out then quantity of water taken out is.
a. 3
b. 6
c. 9
d. 1
16. which is the 4 digit number whose second digit is thrice the first digit and 3'rd digit is sum of 1'st and 2'nd and last digit is twice the second digit.
1.2674
2.1349.
3.3343
4.3678
17. In a straight highway 2 cars starts from the same point in opposite directions each travels for 8 Kms and takeleft turn then travel for 6 Kms what is the distance between them now.
1.16
2.20
3.25
4.10
Technical Section
1. In ANSI C which is such thing is not in Java.
typedef struct node
{
int
NODEPTR * NODE
}
2. Q. In signed magnitude notation what is the minimum value that can be represented with 8 bits
a) -128 b) -255 c) -127 d) 0
3. Q. there is an employer table with key feilds as employer no. data in every n'th row are needed for a simple followingqueries will get required results.
a) select A employe no. from employe A , where exists from employe B where A employe no. = B employehaving (count(*) mod n)=0
b) select employe no. from employe A, employe B where A employe no. = B employ no.grouply employe no. having (count(*) mod n=0 )
c) both a& b
d) none of the above
4. Piggybacking is done for, Ans=>Acknowledgement.
5. WHICH IS NOT BASIC data type ans.Char*
6. which of the following statement is valid for string copy
char *srt,*ptr;
a) while(*str) {
*str=*ptr;
++str=++ptr;
}
b ) while(*str)
{*++str=*++ptr};
c)
7. Two variable cannt have the same name in
a)function b) block c) file d)--- C Section
8. #define inc(x) x++
main()
{
int t=1;
printf("%d",inc(t++));
}
9. one or two que for the complicated declaration.
10. Const char *a="Abcd"; char const *a="lmno"; base do this,Two que were there.
11. char *p ;
char q[20];
12. int i,*p=&i;
p=malloc(10);
free(p);
printf("%d",p);
ans : garbage
13. int i=20,*j=&i
f(i)
printf("%d",i);
14. #define val 1+2
printf("%d%d",val/val,val^3)
ans : 3 9
15. #define "this" "#"
#define (x,y) x##y
printf("this","this is")
ans: compilation error (tested)
16. 2^2)+(a^a)
17. int a ,b=7
a=b<4?b<<1:b>4?7>>1:a
ans.3
18. one que on c++ class member function
ans.d
19. work of memory management unit.
20. who relate virtual memory to physical memory ans.os
21. memory is allocated to variable
a)when declared b)when define c)...
22. Question on double linked list
23. Define success 1
define failure -1
if(condition)
printf(success);
else
printf(failure);
ans success
24. main()
{
int var=25,varp;
varp=&var;
varp=10;
fun(varp);
printf(%d%d",var,varp);
ans a)45,45 b)55,55 c) 20,55;
25. u r given two statements
a=(10.15);
b=10,15;
if they are executed what is the output printf("%d%d",a,b);
a)10,15 b)15,10 c)10,10 d)15,15 ans a
26. #define inc(x) x++
main()
{
int t=1;
printf("%d",inc(t++));
}
ans.error
27. main
{int x=1,y=2,z=3;
x=y==z;
printf(x);
}
TCS QUE
TCS PAPER - 01 JUN 2006 - KOLKATTA
Hi Chetanaites
I am Abhijit Chakraborty, recently I have been campus recruited from GNIT kolkata by TCS.I am a third year student from electrical background and as you know it's a tough competition for us to enter the software profession..I have found that there is no material for electrical department so I am compiling and sending my preparation to you all.
The test was online and written both.
I am sending you the questions.
Paper consisted of three sections.They are as .
Verbal-30Q-20mins
Logical/Quantitative-38Q-40mins
Critical-12Q-30mins
So the total exam is for 50mins and not 60 mins as it had been told by most of the passouts who got through..For online test there is a specific time cut-out based on the qubex software they have used but for the written there is no time scheduling you can start anywhere you like..
Cut off for written was 50 and for online it was 42 and not 38 as told by the others..
Now the questions that came.
Verbal: Synonyms:
Brim
Renounce
Caprice
Brash
Limber
Admonish
Tranquil
Moribund
Mundane
Antonyms (This came mostly from GRE Barron's Antonyms exercise)
Encumber
Opacity
Bilk
Luminary
Spur
Stupefy
Pulchritude
Slack
Occlude
Ambiguity
Logical/Quatitative:
Complete the series 2, 7, 24, 77, ----? Ans: 238
find value ##+25-++# 16 , where # denotes double and + denotes square root
Ans: 621
in a two dimensional array X(9,7) which each element occupying 4 bytes of memory with address of the first element X(1,1) is 3000, find the address of X(8,5).
Ans: 3212
In the word ORGANISATIONAL if the first and second, third and fourth, fourth and fifth, fifth and sixth words are interchanged up to the last letter, what would be the tenth letter from right????
Ans:I
What is the largest Prime Number that can be stored in 8-bit memory?
Ans:251
Select odd one out Java, LISP, SMALLTALK, EIFFEL Ans: effiel
Select odd one out sql, DB2, SYBASE, HTTP Ans:HTTP
The size of program is n. and the memory occupied by the program is given by M= square root of 4000n.if the size of the program is increased by 1% then how much memory now occupied? Ans:0.5%(SQRT 101N)
A and B do a work in 7 days. If A does double as B the how many days take A to do? Ans: 10.5
Find the value of the 678 to the base 7. Ans: 1656
Which of the following highest Standard deviation
7, - 7, 7,-7, 7,-7 b) 7, 7, 7,7,7,7 c) -7, - 7, -7,-7,-7,-7 d) -7, 7, -7, 7,-7, 7 Ans: d)
Which of the following is power of 3 a) 2345 b) 9875 c) 6504 d) 9833
Ans: c)
Which of the following is integer? a) 451/45 b) 8765676/17 c) 34567/76 d) 567845/19 Ans: b)
find the result of the following expression if , M denotes modules operation, R denotes round-off, T denotes truncations M(373,5)+R(3.4) +T(7,7)+R(5,8)
Ans: 19
If TAFJHH is coded as RBEKGI then RBDJK can be coded as?
Ans: qcckj
16.g(0)= -1, G(1)=1 ,G(N) = G(N-1)-G(N-2) , g(6)=? Ans: -2
A power unit is there by the bank of the river of 900 mtr width. a cable is made from power unit to power a plant opposite to that of the river and 3000 mtr away from the power unit. The cost of the cable bellows water Rs5 / mtr and cost of cable on the bank is Rs 4/ mtr. Find the total of laying the cable.
Ans: 12900
In madras, temperature at noon varies according to -t^2/2 + 8t + 3, where t is elapsed time. Find how much tem more or less in 4 pm to 9 pm.
Ans: At 9pm 7.5 more chetana-jobs
The size of the bucket is N kb. The bucket fills at the rate of 0.1 kb per millisecond. A programmer sends a program to receiver. There it waits for 10 milliseconds / and response will be back to programmer in 20 millisecond. How many much time the program takes to get a response back to programmer, after it is sent?
Ans: 30 millisecond
Which of the following do not form triangle? a)5,5,5 b) 3,4,7, c) 3,5,9 d) 81,8,5
Ans: c) options are not right
Which of the following are orthogonal pairs a) 3i+2j b) i+j c) 2i-3j d) 7i+j
Ans: a) + c)
If A, B, C are the mechanisms used separately to reduce the wastage of fuel by 30%, 20%, 10%. What will be the fuel economy if they were used combine?
Ans: 49.6
What is the max possible 3 digit prime number?
Ans: 997
If the vertex (5,7) is placed in the memory. First vertex (1,1) s address is 1245 and then address of (5,7) is ----------
Ans: 1279
A can copy 50 papers in 10 hours while both A & B can copy 70 papers in 10 hours. Then for how many hours required for B to copy 26 papers?
Ans: 13 hours
My flight takes of at 2am from a place at 18N 10E and landed 10 Hrs later at a place with coordinates 36N70W. What is the local time when my plane landed?
Ans: 6.40 am
The number 384 in decimal system is given by (1234) x in the X System of numbers find the value of X a} 5 b) 6 c) 7 d) 8 e) 9
Ans: a)
A man, a woman, and a child can do a piece of work in 6 days. Man only can do it in 24 days. Woman can do it in 16 days and in how many days child can do the same work? Ans: 16
Complete the series. 3, 8, --, 24, --, 48, 63. Ans: 15,35
WHICH SHAPE WILL BE OBTAINED BY USING THESE VALUES OF X ,Y
X Y
0 0.00001
10 1.02
100 1.72
1000 3.00
9999 4.72
Ans: Y= log10(X)
33. VENN DIAGROM below HOW MANY PERSON KNOW ENGLISH MORE THAN FRENCH. HOW MUCH % OF PEOPLE KNOWS ALL THE 3 LANGUAGES. HOW MUCH % OF PEOPLE THOSE WHO KNOWS FRENCH AND GERMAN AND NOT ENGLISH
34. Number of faces, vertices and edges of a cube Ans: 6,8 , 12
http://www.ChetanaS.com
35. A, B and C are 8 bit no's. They are as follows:
A -> 1 1 0 1 1 0 1 1
B -> 0 1 1 1 1 0 1 0
C -> 0 1 1 0 1 1 0 1 (n=intersection, u=union)
Find ((A n B) u C) =? Ans: 29…. A-B is {A} - {A n B}
36. A finishes the work in 10 days & B in 8 days individually. If A works for only 6 days then how many days should B work to complete A's work? Ans: 3.2 days
And few questions from venn diagram..
Critical:
1> Puzzle of a motorist going for the shortest route from city A to city C..
2> Puzzle of the two marriage group in a community,i.e Red and Green..
3> Puzzle that all K's are J's..
All the three are repeated from the model testpaper 1 from GRE Barron's 12th edition.
Regarding the aptitude please go through the GRE barron's antonym exercise and model test papers.This will also do for critical reasoning. Other that this for logical or quatitative go through the past papers you will get through..
Interview:
There was only one person in my panel.But he was more that enough..
Person:Intoduce yourself?
Me:bla bla..
Person:So you r from electrical,and subjest of interest is digital?
Me yes
Person:But how about machine?
Me: I know the basics.
Person:Draw the torque slip grap for single and 3 phase induction motor?
Me: Drawn and explained
Person:Convert the number 32 to octal and hexadecimal?
Me:Done with no problem.
Person:Do you know corona in power system?
Me:Yes,sir and I explained it to him.
Person:How to reduce them?
Me:I explained the various method of reducing corona.
Person:Why do we use octal number system?
Me:To get the tedious long binary data into small memory of the digital circuits.
Person:How in microprossecor 8085 the instructions are executed?
Me:Explained the whole working of 8085 microprocessor
Person:What is stack in data structure and its repective operation?
Me:Explained it and its push pop algorithms explined properly
Person:What do you know in 'C'?
Me:Just the Basics chetanasinterview.com
Person:Write a programe using structure to draw the result for a class?
Me:Written it with no trouble..
http://www.chetanasinterview.com
At this he was very much impressed and asked me if I am feeling comfortable as I was smiling at his every word. I said I am all right. He bid me best of luck and recommended me to HR.
HR Interview:
As I have given 'HANDWRITING ANALYSIS' as my hobby so the two HR person kept on writing pages after pages and gave me to analyse,as I was strong in this groun so I hit the bulls eye and I was selected..To get success through HR write a peculiar hobby and grow interest for it and you are sure to clear it with no doubts..e.g- stock market,finding information about super computers..
APPS
Aptitude Questions
1.One of the following is my secret word:AIM DUE MOD OAT TIE.With the list in front of you, if I were to tell you any one of my secret word, then you would be able to tell me the number of vowels in my secret word.Which is my secret word?
Ans.TIE
2.In the following figure:A B C
D
E F G
H
I
Each of the digits 1, 2, 3, 4, 5, 6, 7, 8, and 9 is:
a)Represented by a different letter in the figure above.
b)Positioned in the figure above so that each of A + B + C,C + D +E,E + F + G, and G + H + I is equal to 13.
Which digit does E represent?
Ans.E is 4
3.One of Mr. Horton,his wife,their son,and Mr. Horton's mother is a doctor and another is a lawyer.
a)If the doctor is younger than the lawyer, then the doctor and the lawyer are not blood relatives.
b)If the doctor is a woman, then the doctor and the lawyer are blood relatives.
c)If the lawyer is a man, then the doctor is a man.
Whose occupation you know?
Ans.Mr. Horton:he is the doctor.
4.Here is a picture of two cubes:
a)The two cubes are exactly alike.
b)The hidden faces indicated by the dots have the same alphabet on them.
Which alphabet-q, r, w, or k is on the faces indicated by the dots?
Ans.q
5.In the following figure:
A D
B G E
C F
Each of the seven digits from 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9 is:
a)Represented by a different letter in the figure above.
b)Positioned in the figure above so that A*B*C,B*G*E, and D*E*F are equal.
Which digit does G represent?
Ans.G represents the digit 2.
6.Mr. and Mrs. Aye and Mr. and Mrs. Bee competed in a chess tournament.Of the three games played:
a)In only the first game werethe two players married to each other.
b)The men won two games and the women won one game.
c)The Ayes won more games than the Bees.
d)Anyone who lost game did not play the subsequent game.
Who did not lose a game?
Ans.Mrs.Bee did not lose a game.
7.Three piles of chips--pile I consists one chip, pile II consists of chips, and pile III consists of three chips--are to be used in game played by Anita and Brinda.The game requires:
a)That each player in turn take only one chip or all chips from just one pile.
b)That the player who has to take the last chip loses.
c)That Anita now have her turn.
From which pile should Anita draw in order to win?
Ans.Pile II
8.Of Abdul, Binoy, and Chandini:
a)Each member belongs to the Tee family whose members always tell the truth or to the El family whose members always lie.
b)Abdul says ''Either I belong or Binoy belongs to a different family from the other two."
Whose family do you name of?
Ans.Binoy's family--El.
9.In a class composed of x girls and y boys what part of the class is composed of girls
A.y/(x + y)
B.x/xy
C.x/(x + y)
D.y/xy
Ans.C
10.What is the maximum number of half-pint bottles of cream that can be filled with a 4-gallon can of cream(2 pt.=1 qt. and 4 qt.=1 gal)
A.16
B.24
C.30
D.64
Ans.D
11.If the operation,^ is defined by the equation x ^ y = 2x + y,what is the value of a in 2 ^ a = a ^ 3
A.0
B.1
C.-1
D.4
Ans.B
12.A coffee shop blends 2 kinds of coffee,putting in 2 parts of a 33p. a gm. grade to 1 part of a 24p. a gm.If the mixture is changed to 1 part of the 33p. a gm. to 2 parts of the less expensive grade,how much will the shop save in blending 100 gms.
A.Rs.90
B.Rs.1.00
C.Rs.3.00
D.Rs.8.00
Ans.C
13.There are 200 questions on a 3 hr examination.Among these questions are 50 mathematics problems.It is suggested that twice as much time be spent on each maths problem as for each other question.How many minutes should be spent on mathematics problems
A.36
B.72
C.60
D.100
Ans.B
14.In a group of 15,7 have studied Latin, 8 have studied Greek, and 3 have not studied either.How many of these studied both Latin and Greek
A.0
B.3
C.4
D.5
Ans.B
15.If 13 = 13w/(1-w) ,then (2w)2 =
A.1/4
B.1/2
C.1
D.2
Ans.C
16. If a and b are positive integers and (a-b)/3.5 = 4/7, then
(A) b < a
(B) b > a
(C) b = a
(D) b >= a
Ans. A
17. In june a baseball team that played 60 games had won 30% of its game played. After a phenomenal winning streak this team raised its average to 50% .How many games must the team have won in a row to attain this average?
A. 12
B. 20
C. 24
D. 30
Ans. C
18. M men agree to purchase a gift for Rs. D. If three men drop out how much more will each have to contribute towards the purchase of the gift/
A. D/(M-3)
B. MD/3
C. M/(D-3)
D. 3D/(M2-3M)
Ans. D
19. A company contracts to paint 3 houses. Mr.Brown can paint a house in 6 days while Mr.Black would take 8 days and Mr.Blue 12 days. After 8 days Mr.Brown goes on vacation and Mr. Black begins to work for a period of 6 days. How many days will it take Mr.Blue to complete the contract?
A. 7
B. 8
C. 11
D. 12
Ans.C
20. 2 hours after a freight train leaves Delhi a passenger train leaves the same station travelling in the same direction at an average speed of 16 km/hr. After travelling 4 hrs the passenger train overtakes the freight train. The average speed of the freight train was?
A. 30
B. 40
C.58
D. 60
Ans. B
21. If 9x-3y=12 and 3x-5y=7 then 6x-2y = ?
A.-5
B. 4
C. 2
D. 8
Ans. D
22. There are 5 red shoes, 4 green shoes. If one draw randomly a shoe what is the probability of getting a red shoe
Ans 5c1/ 9c1
23. What is the selling price of a car? If the cost of the car is Rs.60 and a profit of 10% over selling price is earned
Ans: Rs 66/-
24. 1/3 of girls , 1/2 of boys go to canteen .What factor and total number of classmates go to canteen.
Ans: Cannot be determined.
25. The price of a product is reduced by 30% . By what percentage should it be increased to make it 100%
Ans: 42.857%
26. There is a square of side 6cm . A circle is inscribed inside the square. Find the ratio of the area of circle to square.
Ans. 11/14
27. There are two candles of equal lengths and of different thickness. The thicker one lasts of six hours. The thinner 2 hours less than the thicker one. Ramesh lights the two candles at the same time. When he went to bed he saw the thicker one is twice the length of the thinner one. How long ago did Ramesh light the two candles .
Ans: 3 hours.
28. If M/N = 6/5,then 3M+2N = ?
29. If p/q = 5/4 , then 2p+q= ?
30. If PQRST is a parallelogram what it the ratio of triangle PQS & parallelogram PQRST .
Ans: 1:2
31. The cost of an item is Rs 12.60. If the profit is 10% over selling price what is the selling price ?
Ans: Rs 13.86/-
32. There are 6 red shoes & 4 green shoes . If two of red shoes are drawn what is the probability of getting red shoes
Ans: 6c2/10c2
33. To 15 lts of water containing 20% alcohol, we add 5 lts of pure water. What is % alcohol.
Ans : 15%
34. A worker is paid Rs.20/- for a full days work. He works 1,1/3,2/3,1/8.3/4 days in a week. What is the total amount paid for that worker ?
Ans : 57.50
35. If the value of x lies between 0 & 1 which of the following is the largest?
(a) x
(b) x2
(c) -x
(d) 1/x
Ans : (d)
36. If the total distance of a journey is 120 km .If one goes by 60 kmph and comes back at 40kmph what is the average speed during the journey?
Ans: 48kmph
37. A school has 30% students from Maharashtra .Out of these 20% are Bombey students. Find the total percentage of Bombay?
Ans: 6%
38. An equilateral triangle of sides 3 inch each is given. How many equilateral triangles of side 1 inch can be formed from it?
Ans: 9
39. If A/B = 3/5,then 15A = ?
Ans : 9B
40. Each side of a rectangle is increased by 100% .By what percentage does the area increase?
Ans : 300%
41. Perimeter of the back wheel = 9 feet, front wheel = 7 feet on a certain distance, the front wheel gets 10 revolutions more than the back wheel .What is the distance?
Ans : 315 feet.
42. Perimeter of front wheel =30, back wheel = 20. If front wheel revolves 240 times. How many revolutions will the back wheel take?
Ans: 360 times
43. 20% of a 6 litre solution and 60% of 4 litre solution are mixed. What percentage of the mixture of solution
Ans: 36%
44City A's population is 68000, decreasing at a rate of 80 people per year. City B having population 42000 is increasing at a rate of 120 people per year. In how many years both the cities will have same population?
Ans: 130 years
45Two cars are 15 kms apart. One is turning at a speed of 50kmph and the other at 40kmph . How much time will it take for the two cars to meet?
Ans: 3/2 hours
46A person wants to buy 3 paise and 5 paise stamps costing exactly one rupee. If he buys which of the following number of stamps he won't able to buy 3 paise stamps.
Ans: 9
47There are 12 boys and 15 girls, How many different dancing groups can be formed with 2 boys and 3 girls.
48Which of the following fractions is less than 1/3
(a) 22/62
(b) 15/46
(c) 2/3
(d) 1
Ans: (b)
49There are two circles, one circle is inscribed and another circle is circumscribed over a square. What is the ratio of area of inner to outer circle?
Ans: 1 : 2
50Three types of tea the a,b,c costs Rs. 95/kg,100/kg and70/kg respectively.
How many kgs of each should be blended to produce 100 kg of mixture worth Rs.90/kg,
given that the quntities of band c are equal
a)70,15,15
b)50,25,25
c)60,20,20
d)40,30,30
Ans. (b)
51. in a class, except 18 all are above 50 years.
15 are below 50 years of age. How many people are there
(a) 30
(b) 33
(c) 36
(d) none of these.
Ans. (d)
52. If a boat is moving in upstream with velocity of 14 km/hr and goes downstream with a velocity of 40 km/hr, then what is the speed of the stream ?
(a) 13 km/hr
(b) 26 km/hr
(c) 34 km/hr
(d) none of these
Ans. A
53. Find the value of ( 0.75 * 0.75 * 0.75 - 0.001 ) / ( 0.75 * 0.75 - 0.075 + 0.01)
(a) 0.845
(b) 1.908
(c) 2.312
(d) 0.001
Ans. A
54. A can have a piece of work done in 8 days, B can work three times faster than the A, C can work five times faster than A. How many days will they take to do the work together ?
(a) 3 days
(b) 8/9 days
(c) 4 days
(d) can't say
Ans. B
55. A car travels a certain distance taking 7 hrs in forward journey, during the return journey increased speed 12km/hr takes the times 5 hrs.What is the distance travelled
(a) 210 kms
(b) 30 kms
(c) 20 kms
(c) none of these
Ans. B
56. Instead of multiplying a number by 7, the number is divided by 7. What is the percentage of error obtained ?
57. Find (7x + 4y ) / (x-2y) if x/2y = 3/2 ?
(a) 6
(b) 8
(c) 7
(d) data insufficient
Ans. C
58. A man buys 12 lts of liquid which contains 20% of the liquid and the rest is water. He then mixes it with 10 lts of another mixture with 30% of liquid.What is the % of water in the new mixture?
59. If a man buys 1 lt of milk for Rs.12 and mixes it with 20% water and sells it for Rs.15, then what is the percentage of gain?
60. Pipe A can fill a tank in 30 mins and Pipe B can fill it in 28 mins.If 3/4th of the tank is filled by Pipe B alone and both are opened, how much time is required by both the pipes to fill the tank completely ?
61. If on an item a company gives 25% discount, they earn 25% profit. If they now give 10% discount then what is the profit percentage.
(a) 40%
(b) 55%
(c) 35%
(d) 30%
Ans. D
62. A certain number of men can finish a piece of work in 10 days. If however there were 10 men less it will take 10 days more for the work to be finished. How many men were there originally?
(a) 110 men
(b) 130 men
(c) 100 men
(d) none of these
Ans. A
63. In simple interest what sum amounts of Rs.1120/- in 4 years and Rs.1200/- in 5 years ?
(a) Rs. 500
(b) Rs. 600
(c) Rs. 800
(d) Rs. 900
Ans. C
64. If a sum of money compound annually amounts of thrice itself in 3 years. In how many years
will it become 9 times itself.
(a) 6
(b) 8
(c) 10
(d) 12
Ans A
65. Two trains move in the same direction at 50 kmph and 32 kmph respectively. A man in the slower train
observes the 15 seconds elapse before the faster train completely passes by him.
What is the length of faster train ?
(a) 100m
(b) 75m
(c) 120m
(d) 50m
Ans B
66. How many mashes are there in 1 squrare meter of wire gauge if each mesh
is 8mm long and 5mm wide ?
(a) 2500
(b) 25000
(c) 250
(d) 250000
Ans B
67. x% of y is y% of ?
(a) x/y
(b) 2y
(c) x
(d) can't be determined
Ans. C
68. The price of sugar increases by 20%, by what % should a housewife reduce the consumption of sugar so that expenditure on sugar can be same as before ?
(a) 15%
(b) 16.66%
(c) 12%
(d) 9%
Ans B
69. A man spends half of his salary on household expenses, 1/4th for rent, 1/5th for travel expenses, the man deposits the rest in a bank. If his monthly deposits in the bank amount 50, what is his monthly salary ?
(a) Rs.500
(b) Rs.1500
(c) Rs.1000
(d) Rs. 900
Ans C
70. The population of a city increases @ 4% p.a. There is an additional annual increase of 4% of the population due to the influx of job seekers, find the % increase in population after 2 years ?
71. The ratio of the number of boys and girls in a school is 3:2 Out of these 10% the boys and 25% of girls are scholarship holders. % of students who are not scholarship holders.?
72. 15 men take 21 days of 8 hrs. each to do a piece of work. How many days of 6 hrs. each would it take for 21 women if 3 women do as much work as 2 men?
(a) 30
(b) 20
(c) 19
(d) 29
Ans. A
73. A cylinder is 6 cms in diameter and 6 cms in height. If spheres of the same size are made from the material obtained, what is the diameter of each sphere?
(a) 5 cms
(b) 2 cms
(c) 3 cms
(d) 4 cms
Ans C
74. A rectangular plank (2)1/2 meters wide can be placed so that it is on either side of the diagonal of a square shown below.(Figure is not available)What is the area of the plank?
Ans :7*(2)1/2
75. The difference b/w the compound interest payble half yearly and the simple interest on a
certain sum lent out at 10% p.a for 1 year is Rs 25. What is the sum?
(a) Rs. 15000
(b) Rs. 12000
(c) Rs. 10000
(d) none of these
Ans C
76. What is the smallest number by which 2880 must be divided in order to make it into a
perfect square ?
(a) 3
(b) 4
(c) 5
(d) 6
Ans. C
77. A father is 30 years older than his son however he will be only thrice as old as the son after 5 years
what is father's present age ?
(a) 40 yrs
(b) 30 yrs
(c) 50 yrs
(d) none of these
Ans. A
78. An article sold at a profit of 20% if both the cost price and selling price would be Rs.20/- the profit would be 10% more. What is the cost price of that article?
29. If an item costs Rs.3 in '99 and Rs.203 in '00.What is the % increase in price?
(a) 200/3 %
(b) 200/6 %
(c) 100%
(d) none of these
Ans. A
80. 5 men or 8 women do equal amount of work in a day. a job requires 3 men and 5 women to finish the job in 10 days how many woman are required to finish the job in 14 days.
a) 10
b) 7
c) 6
d) 12
Ans 7
81. A simple interest amount of rs 5000 for six month is rs 200. what is the anual rate of interest?
a) 10%
b) 6%
c) 8%
d) 9%
Ans 8%
82. In objective test a correct ans score 4 marks and on a wrong ans 2 marks are ---. a student score 480 marks from 150 question. how many ans were correct?
a) 120
b) 130
c) 110
d) 150
Ans130.
83. An artical sold at amount of 50% the net sale price is rs 425 .what is the list price of the artical?
a) 500
b) 488
c) 480
d) 510
Ans 500
84. A man leaves office daily at 7pm A driver with car comes from his home to pick him from office and bring back home
One day he gets free at 5:30 and instead of waiting for driver he starts walking towards home.
In the way he meets the car and returns home on car He reaches home 20 minutes earlier than usual.
In how much time does the man reach home usually??
Ans. 1hr 20min
85. A works thrice as much as B. If A takes 60 days less than B to do a work then find the number of days it would take to complete the work if both work together?
Ans. 22½days
86. How many 1's are there in the binary form of 8*1024 + 3*64 + 3
Ans. 4
87. In a digital circuit which was to implement (A B) + (A)XOR(B), the designer implements (A B) (A)XOR(B)
What is the probability of error in it ?
88. A boy has Rs 2. He wins or loses Re 1 at a time If he wins he gets Re 1 and if he loses the game he loses Re 1.
He can loose only 5 times. He is out of the game if he earns Rs 5.
Find the number of ways in which this is possible?
Ans. 16
89. If there are 1024*1280 pixels on a screen and each pixel can have around 16 million colors
Find the memory required for this?
Ans. 4MB
90. On a particular day A and B decide that they would either speak the truth or will lie.
C asks A whether he is speaking truth or lying?
He answers and B listens to what he said. C then asks B what A has said B says "A says that he is a liar"
What is B speaking ?
(a) Truth
(b) Lie
(c) Truth when A lies
(d) Cannot be determined
Ans. (b)
91. What is the angle between the two hands of a clock when time is 8:30
Ans. 75(approx)
92. A student is ranked 13th from right and 8th from left. How many students are there in totality ?
93. A man walks east and turns right and then from there to his left and then 45degrees to
his right.In which direction did he go
Ans. North west
94. A student gets 70% in one subject, 80% in the other. To get an overall of 75% how much should get in third subject.
95. A man shows his friend a woman sitting in a park and says that she the daughter of my grandmother's only son.
What is the relation between the two
Ans. Daughter
96. How many squares with sides 1/2 inch long are needed to cover a rectangle that is 4 ft long and 6 ft wide
(a) 24
(b) 96
(c) 3456
(d) 13824
(e) 14266
97. If a=2/3b , b=2/3c, and c=2/3d what part of d is b/
(a) 8/27
(b) 4/9
(c) 2/3
(d) 75%
(e) 4/3
Ans. (b)
2598Successive discounts of 20% and 15% are equal to a single discount of
(a) 30%
(b) 32%
(c) 34%
(d) 35%
(e) 36
Ans. (b)
99. The petrol tank of an automobile can hold g liters.If a liters was removed when the tank was full, what part of the full tank was removed?
(a)g-a
(b)g/a
(c) a/g
(d) (g-a)/a
(e) (g-a)/g
Ans. (c)
100. If x/y=4 and y is not '0' what % of x is 2x-y
(a)150%
(b)175%
(c)200%
(d)250%
Ans. (b)
Aptitude Questions
1.If 2x-y=4 then 6x-3y=?
(a)15
(b)12
(c)18
(d)10
Ans. (b)
2.If x=y=2z and xyz=256 then what is the value of x?
(a)12
(b)8
(c)16
(d)6
Ans. (b)
3. (1/10)18 - (1/10)20 = ?
(a) 99/1020
(b) 99/10
(c) 0.9
(d) none of these
Ans. (a)
4.Pipe A can fill in 20 minutes and Pipe B in 30 mins and Pipe C can empty the same in 40 mins.If all of them work together, find the time taken to fill the tank
(a) 17 1/7 mins
(b) 20 mins
(c) 8 mins
(d) none of these
Ans. (a)
5. Thirty men take 20 days to complete a job working 9 hours a day.How many hour a day should 40 men work to complete the job?
(a) 8 hrs
(b) 7 1/2 hrs
(c) 7 hrs
(d) 9 hrs
Ans. (b)
6. Find the smallest number in a GP whose sum is 38 and product 1728
(a) 12
(b) 20
(c) 8
(d) none of these
Ans. (c)
7. A boat travels 20 kms upstream in 6 hrs and 18 kms downstream in 4 hrs.Find the speed of the boat in still water and the speed of the water current?
(a) 1/2 kmph
(b) 7/12 kmph
(c) 5 kmph
(d) none of these
Ans. (b)
8. A goat is tied to one corner of a square plot of side 12m by a rope 7m long.Find the area it can graze?
(a) 38.5 sq.m
(b) 155 sq.m
(c) 144 sq.m
(d) 19.25 sq.m
Ans. (a)
9. Mr. Shah decided to walk down the escalator of a tube station. He found that if he walks down 26 steps, he requires 30 seconds to reach the bottom. However, if he steps down 34 stairs he would only require 18 seconds to get to the bottom. If the time is measured from the moment the top step begins to descend to the time he steps off the last step at the bottom, find out the height of the stair way in steps?
Ans.46 steps.
10. The average age of 10 members of a committee is the same as it was 4 years ago, because an old member has been replaced by a young member. Find how much younger is the new member ?
Ans.40 years.
11. Three containers A, B and C have volumes a, b, and c respectively; and container A is full of water while the other two are empty. If from container A water is poured into container B which becomes 1/3 full, and into container C which becomes 1/2 full, how much water is left in container A?
12. ABCE is an isosceles trapezoid and ACDE is a rectangle. AB = 10 and EC = 20. What is the length of AE?
Ans. AE = 10.
13. In the given figure, PA and PB are tangents to the circle at A and B respectively and the chord BC is parallel to tangent PA. If AC = 6 cm, and length of the tangent AP is 9 cm, then what is the length of the chord BC?
Ans. BC = 4 cm.
15 Three cards are drawn at random from an ordinary pack of cards. Find the probability that they will consist of a king, a queen and an ace.
Ans. 64/2210.
16. A number of cats got together and decided to kill between them 999919 mice. Every cat killed an equal number of mice. Each cat killed more mice than there were cats. How many cats do you think there were ?
Ans. 991.
17. If Log2 x - 5 Log x + 6 = 0, then what would the value / values of x be?
Ans. x = e2 or e3.
18. The square of a two digit number is divided by half the number. After 36 is added to the quotient, this sum is then divided by 2. The digits of the resulting number are the same as those in the original number, but they are in reverse order. The ten's place of the original number is equal to twice the difference between its digits. What is the number?
Ans. 46
19.Can you tender a one rupee note in such a manner that there shall be total 50 coins but none of them would be 2 paise coins.?
Ans. 45 one paisa coins, 2 five paise coins, 2 ten paise coins, and 1 twenty-five paise coins.
20.A monkey starts climbing up a tree 20ft. tall. Each hour, it hops 3ft. and slips back 2ft. How much time would it take the monkey to reach the top?
Ans.18 hours.
21. What is the missing number in this series? 8 2 14 6 11 ? 14 6 18 12
Ans. 9
22. A certain type of mixture is prepared by mixing brand A at Rs.9 a kg. with brand B at Rs.4 a kg. If the mixture is worth Rs.7 a kg., how many kgs. of brand A are needed to make 40kgs. of the mixture?
Ans. Brand A needed is 24kgs.
23. A wizard named Nepo says "I am only three times my son's age. My father is 40 years more than twice my age. Together the three of us are a mere 1240 years old." How old is Nepo?
Ans. 360 years old.
24. One dog tells the other that there are two dogs in front of me. The other one also shouts that he too had two behind him. How many are they?
Ans. Three.
25. A man ate 100 bananas in five days, each day eating 6 more than the previous day. How many bananas did he eat on the first day?
Ans. Eight.
26. If it takes five minutes to boil one egg, how long will it take to boil four eggs?
Ans. Five minutes.
27. The minute hand of a clock overtakes the hour hand at intervals of 64 minutes of correct time. How much a day does the clock gain or lose?
Ans. 32 8/11 minutes.
28. Solve for x and y: 1/x - 1/y = 1/3, 1/x2 + 1/y2 = 5/9.
Ans. x = 3/2 or -3 and y = 3 or -3/2.
29. Daal is now being sold at Rs. 20 a kg. During last month its rate was Rs. 16 per kg. By how much percent should a family reduce its consumption so as to keep the expenditure fixed?
Ans. 20 %.
30. Find the least value of 3x + 4y if x2y3 = 6.
Ans. 10.
31. Can you find out what day of the week was January 12, 1979?
Ans. Friday.
32. A garrison of 3300 men has provisions for 32 days, when given at a rate of 850 grams per head. At the end of 7 days a reinforcement arrives and it was found that now the provisions will last 8 days less, when given at the rate of 825 grams per head. How, many more men can it feed?
Ans. 1700 men.
33. From 5 different green balls, four different blue balls and three different red balls, how many combinations of balls can be chosen taking at least one green and one blue ball?
Ans. 3720.
34. Three pipes, A, B, & C are attached to a tank. A & B can fill it in 20 & 30 minutes respectively while C can empty it in 15 minutes. If A, B & C are kept open successively for 1 minute each, how soon will the tank be filled?
Ans. 167 minutes.
35. A person walking 5/6 of his usual rate is 40 minutes late. What is his usual time? Ans. 3 hours 20 minutes.
36.For a motorist there are three ways going from City A to City C. By way of bridge the distance is 20 miles and toll is $0.75. A tunnel between the two cities is a distance of 10 miles and toll is $1.00 for the vehicle and driver and $0.10 for each passenger. A two-lane highway without toll goes east for 30 miles to city B and then 20 miles in a northwest direction to City C.
1. Which is the shortest route from B to C
(a) Directly on toll free highway to City C
(b) The bridge
(c) The Tunnel
(d) The bridge or the tunnel
(e) The bridge only if traffic is heavy on the toll free highway
Ans. (a)
2. The most economical way of going from City A to City B, in terms of toll and distance is to use the
(a) tunnel
(b) bridge
(c) bridge or tunnel
(d) toll free highway
(e) bridge and highway
Ans. (a)
3. Jim usually drives alone from City C to City A every working day. His firm deducts a percentage of employee pay for lateness. Which factor would most influence his choice of the bridge or the tunnel ?
(a) Whether his wife goes with him
(b) scenic beauty on the route
(c) Traffic conditions on the road, bridge and tunnel
(d) saving $0.25 in tolls
(e) price of gasoline consumed in covering additional 10 miles on the bridge
Ans. (a)
4. In choosing between the use of the bridge and the tunnel the chief factor(s) would be:
I. Traffic and road conditions
II. Number of passengers in the car
III. Location of one's homes in the center or outskirts of one of the cities
IV. Desire to save $0.25
(a) I only
(b) II only
(c) II and III only
(d) III and IV only
(e) I and II only
Ans. (a)
37.The letters A, B, C, D, E, F and G, not necessarily in that order, stand for seven consecutive integers from 1 to 10
D is 3 less than A
B is the middle term
F is as much less than B as C is greater than D
G is greater than F
1. The fifth integer is
(a) A
(b) C
(c) D
(d) E
(e) F
Ans. (a)
2. A is as much greater than F as which integer is less than G
(a) A
(b) B
(c) C
(d) D
(e) E
Ans. (a)
3. If A = 7, the sum of E and G is
(a) 8
(b) 10
(c) 12
(d) 14
(e) 16
Ans. (a)
4. A - F = ?
(a) 1
(b) 2
(c) 3
(d) 4
(e) Cannot be determined
Ans. (a)
5. An integer T is as much greater than C as C is greater than E. T can be written as A + E. What is D?
(a) 2
(b) 3
(c) 4
(d) 5
(e) Cannot be determined
Ans. (a)
6. The greatest possible value of C is how much greater than the smallest possible value of D?
(a) 2
(b) 3
(c) 4
(d) 5
(e) 6
Ans. (a)
38.
1. All G's are H's
2. All G's are J's or K's
3. All J's and K's are G's
4. All L's are K's
5. All N's are M's
6. No M's are G's
1. If no P's are K's, which of the following must be true?
(a) All P's are J's
(b) No P is a G
(c) No P is an H
(d) If any P is an H it is a G
(e) If any P is a G it is a J
Ans. (a)
2. Which of the following can be logically deduced from the conditions stated?
(a) No M's are H's
(b) No M's that are not N's are H's
(c) No H's are M's
(d) Some M's are H's
(e) All M's are H's
Ans. (a)
3. Which of the following is inconsistent with one or more of the conditions?
(a) All H's are G's
(b) All H's that are not G's are M's
(c) Some H's are both M's and G's
(d) No M's are H's
(e) All M's are H's
Ans. (a)
4. The statement "No L's are J's" is
I. Logically deducible from the conditions stated
II. Consistent with but not deducible from the conditions stated
III. Deducible from the stated conditions together with the additional statement "No J's are K's"
(a) I only
(b) II only
(c) III only
(d) II and III only
(e) Neither I, II nor III
Ans. (a)
39.In country X, democratic, conservative and justice parties have fought three civil wars in twenty years. TO restore stability an agreement is reached to rotate the top offices President, Prime Minister and Army Chief among the parties so that each party controls one and only one office at all times. The three top office holders must each have two deputies, one from each of the other parties. Each deputy must choose a staff composed of equally members of his or her chiefs party and member of the third party.
1. When Justice party holds one of the top offices, which of the following cannot be true
(a) Some of the staff members within that office are justice party members
(b) Some of the staff members within that office are democratic party members
(c) Two of the deputies within the other offices are justice party members
(d) Two of the deputies within the other offices are conservative party members
(e) Some of the staff members within the other offices are justice party members.
Ans. (a)
2. When the democratic party holds presidency, the staff of the prime minister's deputies are composed
I. One-fourth of democratic party members
II. One-half of justice party members and one-fourth of conservative party members
III. One-half of conservative party members and one-fourth of justice party members.
(a) I only
(b) I and II only
(c) II or III but not both
(d) I and II or I and III
(e) None of these
Ans. (a)
3. Which of the following is allowable under the rules as stated:
(a) More than half of the staff within a given office belonging to a single party
(b) Half of the staff within a given office belonging to a single party
(c) Any person having a member of the same party as his or her immediate superior
(d) Half the total number of staff members in all three offices belonging to a single party
(e) Half the staff members in a given office belonging to parties different from the party of the top office holder in that office.
Ans. (a)
4. The office of the Army Chief passes from Conservative to Justice party. Which of the following must be fired.
(a) The democratic deputy and all staff members belonging to Justice party
(b) Justice party deputy and all his or hers staff members
(c) Justice party deputy and half of his Conservative staff members in the chief of staff office
(d) The Conservative deputy and all of his or her staff members belonging to Conservative party
(e) No deputies and all staff members belonging to conservative parties.
Ans. (a)
40.In recommendations to the board of trustees a tuition increase of $500 per year, the president of the university said "There were no student demonstrations over the previous increases of $300 last year and $200 the year before". If the president's statement is accurate then which of the following can be validly inferred from the information given:
I. Most students in previous years felt that the increases were justified because of increased operating costs.
II. Student apathy was responsible for the failure of students to protest the previous tuition increases.
III. Students are not likely to demonstrate over new tuition increases.
(a) I only
(b) II only
(c) I or II but not both
(d) I, II and III
(e) None
Ans. (a)
41. The office staff of XYZ corporation presently consists of three bookeepers--A, B, C and 5 secretaries D, E, F, G, H. The management is planning to open a new office in another city using 2 bookeepers and 3 secretaries of the present staff . To do so they plan to seperate certain individuals who don't function well together. The following guidelines were established to set up the new office
I. Bookeepers A and C are constantly finding fault with one another and should not be sent together to the new office as a team
II. C and E function well alone but not as a team , they should be seperated
III. D and G have not been on speaking terms and shouldn't go together
IV Since D and F have been competing for promotion they shouldn't be a team
1.If A is to be moved as one of the bookeepers,which of the following cannot be a possible working unit.
A.ABDEH
B.ABDGH
C.ABEFH
D.ABEGH
Ans.B
2.If C and F are moved to the new office,how many combinations are possible
A.1
B.2
C.3
D.4
Ans.A
3.If C is sent to the new office,which member of the staff cannot go with C
A.B
B.D
C.F
D.G
Ans.B
4.Under the guidelines developed,which of the following must go to the new office
A.B
B.D
C.E
D.G
Ans.A
5.If D goes to the new office,which of the following is/are true
I.C cannot go
II.A cannot go
III.H must also go
A.I only
B.II only
C.I and II only
D.I and III only
Ans.D
42.After months of talent searching for an administrative assistant to the president of the college the field of applicants has been narrowed down to 5--A, B, C, D, E .It was announced that the finalist would be chosen after a series of all-day group personal interviews were held.The examining committee agreed upon the following procedure
I.The interviews will be held once a week
II.3 candidates will appear at any all-day interview session
III.Each candidate will appear at least once
IV.If it becomes necessary to call applicants for additonal interviews, no more 1 such applicant should be asked to appear the next week
V.Because of a detail in the written applications,it was agreed that whenever candidate B appears, A should also be present.
VI.Because of travel difficulties it was agreed that C will appear for only 1 interview.
1.At the first interview the following candidates appear A,B,D.Which of the follwing combinations can be called for the interview to be held next week.
A.BCD
B.CDE
C.ABE
D.ABC
Ans.B
2.Which of the following is a possible sequence of combinations for interviews in 2 successive weeks
A.ABC;BDE
B.ABD;ABE
C.ADE;ABC
D.BDE;ACD
Ans.C
3.If A ,B and D appear for the interview and D is called for additional interview the following week,which 2 candidates may be asked to appear with D?
I. A
II B
III.C
IV.E
A.I and II
B.I and III only
C.II and III only
D.III and IV only
Ans.D
4.Which of the following correctly state(s) the procedure followed by the search committee
I.After the second interview all applicants have appeared at least once
II.The committee sees each applicant a second time
III.If a third session,it is possible for all applicants to appear at least twice
A.I only
B.II only
C.III only
D.Both I and II
Ans.A
43. A certain city is served by subway lines A,B and C and numbers 1 2 and 3
When it snows , morning service on B is delayed
When it rains or snows , service on A, 2 and 3 are delayed both in the morning and afternoon
When temp. falls below 30 degrees farenheit afternoon service is cancelled in either the A line or the 3 line,
but not both.
When the temperature rises over 90 degrees farenheit, the afternoon service is cancelled in either the line C or the
3 line but not both.
When the service on the A line is delayed or cancelled, service on the C line which connects the A line, is delayed.
When service on the 3 line is cancelled, service on the B line which connects the 3 line is delayed.
Q1. On Jan 10th, with the temperature at 15 degree farenheit, it snows all day. On how many lines will service be
affected, including both morning and afternoon.
(A) 2
(B) 3
(C) 4
(D) 5
Ans. D
Q2. On Aug 15th with the temperature at 97 degrees farenheit it begins to rain at 1 PM. What is the minimum number
of lines on which service will be affected?
(A) 2
(B) 3
(C) 4
(D) 5
Ans. C
Q3. On which of the following occasions would service be on the greatest number of lines disrupted.
(A) A snowy afternoon with the temperature at 45 degree farenheit
(B) A snowy morning with the temperature at 45 degree farenheit
(C) A rainy afternoon with the temperature at 45 degree farenheit
(D) A rainy afternoon with the temperature at 95 degree farenheit
Ans. B
44. In a certain society, there are two marriage groups, red and brown. No marriage is permitted within a group. On marriage, males become part of their wives groups; women remain in their own group. Children belong to the same group as their parents. Widowers and divorced males revert to the group of their birth. Marriage to more than one person at the same time and marriage to a direct descendant are forbidden
Q1. A brown female could have had
I. A grandfather born Red
II. A grandmother born Red
III Two grandfathers born Brown
(A) I only
(B) III only
(C) I, II and III
(D) I and II only
Ans. D
Q2. A male born into the brown group may have
(A) An uncle in either group
(B) A brown daughter
(C) A brown son
(D) A son-in-law born into red group
Ans. A
Q3. Which of the following is not permitted under the rules as stated.
(A) A brown male marrying his father's sister
(B) A red female marrying her mother's brother
(C) A widower marrying his wife's sister
(D) A widow marrying her divorced daughter's ex-husband
Ans. B
Q4. If widowers and divorced males retained their group they had upon marrying which of the following would be permissible ( Assume that no previous marriage occurred)
(A) A woman marrying her dead sister's husband
(B) A woman marrying her divorced daughter's ex-husband
(C) A widower marrying his brother's daughter
(D) A woman marrying her mother's brother who is a widower.
Ans. D
Q5. I. All G's are H's
II. All G's are J's or K's
III All J's and K's are G's
IV All L's are K's
V All N's are M's
VI No M's are G's
45. There are six steps that lead from the first to the second floor. No two people can be on the same step
Mr. A is two steps below Mr. C
Mr. B is a step next to Mr. D
Only one step is vacant ( No one standing on that step )
Denote the first step by step 1 and second step by step 2 etc.
1. If Mr. A is on the first step, Which of the following is true?
(a) Mr. B is on the second step
(b) Mr. C is on the fourth step.
(c) A person Mr. E, could be on the third step
(d) Mr. D is on higher step than Mr. C.
Ans: (d)
2. If Mr. E was on the third step & Mr. B was on a higher step than Mr. E which step must be vacant
(a) step 1
(b) step 2
(c) step 4
(d) step 5
(e) step 6
Ans: (a)
3. If Mr. B was on step 1, which step could A be on?
(a) 2&e only
(b) 3&5 only
(c) 3&4 only
(d) 4&5 only
(e) 2&4 only
Ans: (c)
4. If there were two steps between the step that A was standing and the step that B was standing on, and A was on a higher step than D , A must be on step
(a) 2
(b) 3
(c) 4
(d) 5
(e) 6
Ans: (c)
5. Which of the following is false
i. B&D can be both on odd-numbered steps in one configuration
ii. In a particular configuration A and C must either both an odd numbered steps or both an even-numbered steps
iii. A person E can be on a step next to the vacant step.
(a) i only
(b) ii only
(c) iii only
(d) both i and iii
Ans: (c)
46. Six swimmers A, B, C, D, E, F compete in a race. The outcome is as follows.
i. B does not win.
ii. Only two swimmers separate E & D
iii. A is behind D & E
iv. B is ahead of E , with one swimmer intervening
v. F is a head of D
1. Who stood fifth in the race ?
(a) A
(b) B
(c) C
(d) D
(e) E
Ans: (e)
2. How many swimmers seperate A and F ?
(a) 1
(b) 2
(c) 3
(d) 4
(e) cannot be determined
Ans: (d)
3. The swimmer between C & E is
(a) none
(b) F
(c) D
(d) B
(e) A
Ans: (a)
4. If the end of the race, swimmer D is disqualified by the Judges then swimmer B finishes in which place
(a) 1
(b) 2
(c) 3
(d) 4
(e) 5
Ans: (b)
47. Five houses lettered A,B,C,D, & E are built in a row next to each other. The houses are lined up in the order A,B,C,D, & E. Each of the five houses has a colored chimney. The roof and chimney of each housemust be painted as follows.
i. The roof must be painted either green,red ,or yellow.
ii. The chimney must be painted either white, black, or red.
iii. No house may have the same color chimney as the color of roof.
iv. No house may use any of the same colors that the every next house uses.
v. House E has a green roof.
vi. House B has a red roof and a black chimney
1. Which of the following is true ?
(a) At least two houses have black chimney.
(b) At least two houses have red roofs.
(c) At least two houses have white chimneys
(d) At least two houses have green roofs
(e) At least two houses have yellow roofs
Ans: (c)
2. Which must be false ?
(a) House A has a yellow roof
(b) House A & C have different color chimney
(c) House D has a black chimney
(d) House E has a white chimney
(e) House B&D have the same color roof.
Ans: (b)
3. If house C has a yellow roof. Which must be true.
(a) House E has a white chimney
(b) House E has a black chimney
(c) House E has a red chimney
(d) House D has a red chimney
(e) House C has a black chimney
Ans: (a)
4. Which possible combinations of roof & chimney can house
I. A red roof 7 a black chimney
II. A yellow roof & a red chimney
III. A yellow roof & a black chimney
(a) I only
(b) II only
(c) III only
(d) I & II only
(e) I&II&III
Ans: (e)
48. Find x+2y
(i). x+y=10
(ii). 2x+4y=20
Ans: (b)
49. Is angle BAC is a right angle
(i) AB=2BC
(2) BC=1.5AC
Ans: (e)
50. Is x greater than y
(i) x=2k
(ii) k=2y
Ans: (e)
Java Basics
1.The Java interpreter is used for the execution of the source code.
True
False
Ans: a.
2) On successful compilation a file with the class extension is created.
a) True
b) False
Ans: a.
3) The Java source code can be created in a Notepad editor.
a) True
b) False
Ans: a.
4) The Java Program is enclosed in a class definition.
a) True
b) False
Ans: a.
5) What declarations are required for every Java application?
Ans: A class and the main( ) method declarations.
6) What are the two parts in executing a Java program and their purposes?
Ans: Two parts in executing a Java program are:
Java Compiler and Java Interpreter.
The Java Compiler is used for compilation and the Java Interpreter is used for execution of the application.
7) What are the three OOPs principles and define them?
Ans : Encapsulation, Inheritance and Polymorphism are the three OOPs
Principles.
Encapsulation:
Is the Mechanism that binds together code and the data it manipulates, and keeps both safe from outside interference and misuse.
Inheritance:
Is the process by which one object acquires the properties of another object.
Polymorphism:
Is a feature that allows one interface to be used for a general class of actions.
8) What is a compilation unit?
Ans : Java source code file.
9) What output is displayed as the result of executing the following statement?
System.out.println("// Looks like a comment.");
// Looks like a comment
The statement results in a compilation error
Looks like a comment
No output is displayed
Ans : a.
10) In order for a source code file, containing the public class Test, to successfully compile, which of the following must be true?
It must have a package statement
It must be named Test.java
It must import java.lang
It must declare a public class named Test
Ans : b
11) What are identifiers and what is naming convention?
Ans : Identifiers are used for class names, method names and variable names. An identifier may be any descriptive sequence of upper case & lower case letters,numbers or underscore or dollar sign and must not begin with numbers.
12) What is the return type of program’s main( ) method?
Ans : void
13) What is the argument type of program’s main( ) method?
Ans : string array.
14) Which characters are as first characters of an identifier?
Ans : A – Z, a – z, _ ,$
15) What are different comments?
Ans : 1) // -- single line comment
2) /* --
*/ multiple line comment
3) /** --
*/ documentation
16) What is the difference between constructor method and method?
Ans : Constructor will be automatically invoked when an object is created. Whereas method has to be call explicitly.
17) What is the use of bin and lib in JDK?
Ans : Bin contains all tools such as javac, applet viewer, awt tool etc., whereas Lib
contains all packages and variables.
Data types,variables and Arrays
1) What is meant by variable?
Ans: Variables are locations in memory that can hold values. Before assigning any value to a variable, it must be declared.
2) What are the kinds of variables in Java? What are their uses?
Ans: Java has three kinds of variables namely, the instance variable, the local variable and the class variable.
Local variables are used inside blocks as counters or in methods as temporary variables and are used to store information needed by a single method.
Instance variables are used to define attributes or the state of a particular object and are used to store information needed by multiple methods in the objects.
Class variables are global to a class and to all the instances of the class and are useful for communicating between different objects of all the same class or keeping track of global states.
3) How are the variables declared?
Ans: Variables can be declared anywhere in the method definition and can be initialized during their declaration.They are commonly declared before usage at the beginning of the definition.
Variables with the same data type can be declared together. Local variables must be given a value before usage.
4) What are variable types?
Ans: Variable types can be any data type that java supports, which includes the eight primitive data types, the name of a class or interface and an array.
5) How do you assign values to variables?
Ans: Values are assigned to variables using the assignment operator =.
6) What is a literal? How many types of literals are there?
Ans: A literal represents a value of a certain type where the type describes how that value behaves.
There are different types of literals namely number literals, character literals,
boolean literals, string literals,etc.
7) What is an array?
Ans: An array is an object that stores a list of items.
8) How do you declare an array?
Ans: Array variable indicates the type of object that the array holds.
Ex: int arr[];
9) Java supports multidimensional arrays.
a)True
b)False
Ans: a.
10) An array of arrays can be created.
a)True
b)False
Ans: a.
11) What is a string?
Ans: A combination of characters is called as string.
12) Strings are instances of the class String.
a)True
b)False
Ans: a.
13) When a string literal is used in the program, Java automatically creates instances of the string class.
a)True
b)False
Ans: a.
14) Which operator is to create and concatenate string?
Ans: Addition operator(+).
15) Which of the following declare an array of string objects?
String[ ] s;
String [ ]s:
String[ s]:
String s[ ]:
Ans : a, b and d
16) What is the value of a[3] as the result of the following array declaration?
1
2
3
4
Ans : d
17) Which of the following are primitive types?
byte
String
integer
Float
Ans : a.
18) What is the range of the char type?
0 to 216
0 to 215
0 to 216-1
0 to 215-1
Ans. d
19) What are primitive data types?
Ans : byte, short, int, long
float, double
boolean
char
20) What are default values of different primitive types?
Ans : int - 0
short - 0
byte - 0
long - 0 l
float - 0.0 f
double - 0.0 d
boolean - false
char - null
21) Converting of primitive types to objects can be explicitly.
a)True
b)False
Ans: b.
22) How do we change the values of the elements of the array?
Ans : The array subscript expression can be used to change the values of the elements of the array.
23) What is final varaible?
Ans : If a variable is declared as final variable, then you can not change its value. It becomes constant.
24) What is static variable?
Ans : Static variables are shared by all instances of a class.
Operators
1) What are operators and what are the various types of operators available in Java?
Ans: Operators are special symbols used in expressions.
The following are the types of operators:
Arithmetic operators,
Assignment operators,
Increment & Decrement operators,
Logical operators,
Biwise operators,
Comparison/Relational operators and
Conditional operators
2) The ++ operator is used for incrementing and the -- operator is used for
decrementing.
a)True
b)False
Ans: a.
3) Comparison/Logical operators are used for testing and magnitude.
a)True
b)False
Ans: a.
4) Character literals are stored as unicode characters.
a)True
b)False
Ans: a.
5) What are the Logical operators?
Ans: OR(|), AND(&), XOR(^) AND NOT(~).
6) What is the % operator?
Ans : % operator is the modulo operator or reminder operator. It returns the reminder of dividing the first operand by second operand.
7) What is the value of 111 % 13?
3
5
7
9
Ans : c.
8) Is &&= a valid operator?
Ans : No.
9) Can a double value be cast to a byte?
Ans : Yes
10) Can a byte object be cast to a double value ?
Ans : No. An object cannot be cast to a primitive value.
11) What are order of precedence and associativity?
Ans : Order of precedence the order in which operators are evaluated in expressions.
Associativity determines whether an expression is evaluated left-right or right-left.
12) Which Java operator is right associativity?
Ans : = operator.
13) What is the difference between prefix and postfix of -- and ++ operators?
Ans : The prefix form returns the increment or decrement operation and returns the value of the increment or decrement operation.
The postfix form returns the current value of all of the expression and then
performs the increment or decrement operation on that value.
14) What is the result of expression 5.45 + "3,2"?
The double value 8.6
The string ""8.6"
The long value 8.
The String "5.453.2"
Ans : d
15) What are the values of x and y ?
x = 5; y = ++x;
Ans : x = 6; y = 6
16) What are the values of x and z?
x = 5; z = x++;
Ans : x = 6; z = 5
Control Statements
1) What are the programming constructs?
Ans: a) Sequential
b) Selection -- if and switch statements
c) Iteration -- for loop, while loop and do-while loop
2) class conditional {
public static void main(String args[]) {
int i = 20;
int j = 55;
int z = 0;
z = i < j ? i : j; // ternary operator
System.out.println("The value assigned is " + z);
}
}
What is output of the above program?
Ans: The value assigned is 20
3) The switch statement does not require a break.
a)True
b)False
Ans: b.
4) The conditional operator is otherwise known as the ternary operator.
a)True
b)False
Ans: a.
5) The while loop repeats a set of code while the condition is false.
a)True
b)False
Ans: b.
6) The do-while loop repeats a set of code atleast once before the condition is tested.
a)True
b)False
Ans: a.
7) What are difference between break and continue?
Ans: The break keyword halts the execution of the current loop and forces control out of the loop.
The continue is similar to break, except that instead of halting the execution of the loop, it starts the next iteration.
8) The for loop repeats a set of statements a certain number of times until a condition is matched.
a)True
b)False
Ans: a.
9) Can a for statement loop indefintely?
Ans : Yes.
10) What is the difference between while statement and a do statement/
Ans : A while statement checks at the beginning of a loop to see whether the next loop iteration should occur.
A do statement checks at the end of a loop to see whether the next iteration of a loop should occur. The do statement will always execute the body of a loop at least once.
Introduction to Classes and Methods
1) Which is used to get the value of the instance variables?
Ans: Dot notation.
2) The new operator creates a single instance named class and returns a
reference to that object.
a)True
b)False
Ans: a.
3) A class is a template for multiple objects with similar features.
a)True
b)False
Ans: a.
4) What is mean by garbage collection?
Ans: When an object is no longer referred to by any variable, Java automatically
reclaims memory used by that object. This is known as garbage collection.
5) What are methods and how are they defined?
Ans: Methods are functions that operate on instances of classes in which they are defined.Objects can communicate with each other using methods and can call methods in other classes.
Method definition has four parts. They are name of the method, type of object or primitive type the method returns, a list of parameters and the body of the method.
A method's signature is a combination of the first three parts mentioned above.
6) What is calling method?
Ans: Calling methods are similar to calling or referring to an instance variable. These methods are accessed using dot notation.
Ex: obj.methodname(param1,param2)
7) Which method is used to determine the class of an object?
Ans: getClass( ) method can be used to find out what class the belongs to. This class is defined in the object class and is available to all objects.
8) All the classes in java.lang package are automatically imported when
a program is compiled.
a)True
b)False
Ans: a.
9) How can class be imported to a program?
Ans: To import a class, the import keyword should be used as shown.;
import classname;
10) How can class be imported from a package to a program?
Ans: import java . packagename . classname (or) import java.package name.*;
11) What is a constructor?
Ans: A constructor is a special kind of method that determines how an object is
initialized when created.
12) Which keyword is used to create an instance of a class?
Ans: new.
13) Which method is used to garbage collect an object?
Ans: finalize ().
14) Constructors can be overloaded like regular methods.
a)True
b)False
Ans: a.
15) What is casting?
Ans: Casting is bused to convert the value of one type to another.
16) Casting between primitive types allows conversion of one primitive type to another.
a)True
b)False
Ans: a.
17) Casting occurs commonly between numeric types.
a)True
b)False
Ans: a.
18) Boolean values can be cast into any other primitive type.
a)True
b)False
Ans: b.
19) Casting does not affect the original object or value.
a)True
b)False
Ans: a.
20) Which cast must be used to convert a larger value into a smaller one?
Ans: Explicit cast.
21) Which cast must be used to cast an object to another class?
Ans: Specific cast.
22) Which of the following features are common to both Java & C++?
A.The class declaration
b.The access modifiers
c.The encapsulation of data & methods with in objects
d.The use of pointers
Ans: a,b,c.
23) Which of the following statements accurately describe the use of access modifiers within a class definition?
a.They can be applied to both data & methods
b.They must precede a class's data variables or methods
c.They can follow a class's data variables or methods
d.They can appear in any order
e.They must be applied to data variables first and then to methods
Ans: a,b,d.
24) Suppose a given instance variable has been declared private.
Can this instance variable be manipulated by methods out side its class?
a.yes
b.no
Ans: b.
25) Which of the following statements can be used to describe a public method?
a.It is accessible to all other classes in the hierarchy
b.It is accessablde only to subclasses of its parent class
c.It represents the public interface of its class
d.The only way to gain access to this method is by calling one of the public class
methods
Ans: a,c.
26) Which of the following types of class members can be part of the internal part of a class?
a.Public instance variables
b.Private instance variables
c.Public methods
d.Private methods
Ans: b,d.
27) You would use the ____ operator to create a single instance of a named class.
a.new
b.dot
Ans: a.
28) Which of the following statements correctly describes the relation between an object and the instance variable it stores?
a.Each new object has its own distinctive set of instance variables
b.Each object has a copy of the instance variables of its class
c.the instance variable of each object are seperate from the variables of other objects
d.The instance variables of each object are stored together with the variables of other objects
Ans: a,b,c.
29) If no input parameters are specified in a method declaration then the declaration will include __.
a.an empty set of parantheses
b.the term void
Ans: a.
30) What are the functions of the dot(.) operator?
a.It enables you to access instance variables of any objects within a class
b.It enables you to store values in instance variables of an object
c.It is used to call object methods
d.It is to create a new object
Ans: a,b,c.
31) Which of the following can be referenced by this variable?
a.The instance variables of a class only
b.The methods of a class only
c.The instance variables and methods of a class
Ans: c.
32) The this reference is used in conjunction with ___methods.
a.static
b.non-static
Ans: b.
33) Which of the following operators are used in conjunction with the this and super references?
a.The new operator
b.The instanceof operator
c.The dot operator
Ans: c.
34) A constructor is automatically called when an object is instantiated
a. true
b. false
Ans: a.
35) When may a constructor be called without specifying arguments?
a. When the default constructor is not called
b. When the name of the constructor differs from that of the class
c. When there are no constructors for the class
Ans: c.
36) Each class in java can have a finalizer method
a. true
b.false
Ans: a.
37) When an object is referenced, does this mean that it has been identified by the finalizer method for garbage collection?
a.yes
b.no
Ans: b.
38) Because finalize () belongs to the java.lang.Object class, it is present in all ___.
a.objects
b.classes
c.methods
Ans: b.
39) Identify the true statements about finalization.
a.A class may have only one finalize method
b.Finalizers are mostly used with simple classes
c.Finalizer overloading is not allowed
Ans: a,c.
40) When you write finalize() method for your class, you are overriding a finalizer
inherited from a super class.
a.true
b.false
Ans: a.
41) Java memory management mechanism garbage collects objects which are no longer referenced
a true
b.false
Ans: a.
42) are objects referenced by a variable candidates for garbage collection when the variable goes out of scope?
a yes
b. no
Ans: a.
43) Java's garbage collector runs as a ___ priority thread waiting for __priority threads to relinquish the processor.
a.high
b.low
Ans: a,b.
44) The garbage collector will run immediately when the system is out of memory
a.true
b.false
Ans: a.
45) You can explicitly drop a object reference by setting the value of a variable whose data type is a reference type to ___
Ans: null
46) When might your program wish to run the garbage collecter?
a. before it enters a compute-intense section of code
b. before it enters a memory-intense section of code
c. before objects are finalized
d. when it knows there will be some idle time
Ans: a,b,d
47) For externalizable objects the class is solely responsible for the external format of its contents
a.true
b.false
Ans: a
48) When an object is stored, are all of the objects that are reachable from that object stored as well?
a.true
b.false
Ans: a
49) The default__ of objects protects private and trancient data, and supports the __ of the classes
a.evolution
b.encoding
Ans: b,a.
50) Which are keywords in Java?
a) NULL
b) sizeof
c) friend
d) extends
e) synchronized
Ans : d and e
51) When must the main class and the file name coincide?
Ans :When class is declared public.
52) What are different modifiers?
Ans : public, private, protected, default, static, trancient, volatile, final, abstract.
53) What are access modifiers?
Ans : public, private, protected, default.
54) What is meant by "Passing by value" and " Passing by reference"?
Ans : objects – pass by referrence
Methods - pass by value
55) Is a class a subclass of itself?
Ans : A class is a subclass itself.
56) What modifiers may be used with top-level class?
Ans : public, abstract, final.
57) What is an example of polymorphism?
Inner class
Anonymous classes
Method overloading
Method overriding
Ans : c
Packages and interface
1) What are packages ? what is use of packages ?
Ans :The package statement defines a name space in which classes are stored.If you omit the package, the classes are put into the default package.
Signature... package pkg;
Use: * It specifies to which package the classes defined in a file belongs to. * Package is both naming and a visibility control mechanism.
2) What is difference between importing "java.applet.Applet" and "java.applet.*;" ?
Ans :"java.applet.Applet" will import only the class Applet from the package java.applet
Where as "java.applet.*" will import all the classes from java.applet package.
3) What do you understand by package access specifier?
Ans : public: Anything declared as public can be accessed from anywhere
private: Anything declared in the private can’t be seen outside of its class.
default: It is visible to subclasses as well as to other classes in the same package.
4) What is interface? What is use of interface?
Ans : It is similar to class which may contain method’s signature only but not bodies.
Methods declared in interface are abstract methods. We can implement many interfaces on a class which support the multiple inheritance.
5) Is it is necessary to implement all methods in an interface?
Ans : Yes. All the methods have to be implemented.
6) Which is the default access modifier for an interface method?
Ans : public.
7) Can we define a variable in an interface ?and what type it should be ?
Ans : Yes we can define a variable in an interface. They are implicitly final and static.
8) What is difference between interface and an abstract class?
Ans : All the methods declared inside an Interface are abstract. Where as abstract class must have at least one abstract method and others may be concrete or abstract.
In Interface we need not use the keyword abstract for the methods.
9) By default, all program import the java.lang package.
True/False
Ans : True
10) Java compiler stores the .class files in the path specified in CLASSPATH
environmental variable.
True/False
Ans : False
11) User-defined package can also be imported just like the standard packages.
True/False
Ans : True
12) When a program does not want to handle exception, the ______class is used.
Ans : Throws
13) The main subclass of the Exception class is _______ class.
Ans : RuntimeException
14) Only subclasses of ______class may be caught or thrown.
Ans : Throwable
15) Any user-defined exception class is a subclass of the _____ class.
Ans : Exception
16) The catch clause of the user-defined exception class should ______ its
Base class catch clause.
Ans : Exception
17) A _______ is used to separate the hierarchy of the class while declaring an
Import statement.
Ans : Package
18) All standard classes of Java are included within a package called _____.
Ans : java.lang
19) All the classes in a package can be simultaneously imported using ____.
Ans : *
20) Can you define a variable inside an Interface. If no, why? If yes, how?
Ans.: YES. final and static
21) How many concrete classes can you have inside an interface?
Ans.: None
22) Can you extend an interface?
Ans.: Yes
23) Is it necessary to implement all the methods of an interface while implementing the interface?
Ans.: No
24) If you do not implement all the methods of an interface while implementing , what specifier should you use for the class ?
Ans.: abstract
25) How do you achieve multiple inheritance in Java?
Ans: Using interfaces.
26) How to declare an interface example?
Ans : access class classname implements interface.
27) Can you achieve multiple interface through interface?
a)True
b) false
Ans : a.
28) Can variables be declared in an interface ? If so, what are the modifiers?
Ans : Yes. final and static are the modifiers can be declared in an interface.
29) What are the possible access modifiers when implementing interface methods?
Ans : public.
30) Can anonymous classes be implemented an interface?
Ans : Yes.
31) Interfaces can’t be extended.
a)True
b)False
Ans : b.
32) Name interfaces without a method?
Ans : Serializable, Cloneble & Remote.
33) Is it possible to use few methods of an interface in a class ? If so, how?
Ans : Yes. Declare the class as abstract.
Exception Handling
1) What is the difference between ‘throw’ and ‘throws’ ?And it’s application?
Ans : Exceptions that are thrown by java runtime systems can be handled by Try and catch blocks. With throw exception we can handle the exceptions thrown by the program itself. If a method is capable of causing an exception that it does not
handle, it must specify this behavior so the callers of the method can guard
against that exception.
2) What is the difference between ‘Exception’ and ‘error’ in java?
Ans : Exception and Error are the subclasses of the Throwable class. Exception class is used for exceptional conditions that user program should catch. With exception class we can subclass to create our own custom exception.
Error defines exceptions that are not excepted to be caught by you program. Example is Stack Overflow.
3) What is ‘Resource leak’?
Ans : Freeing up other resources that might have been allocated at the beginning of a method.
4)What is the ‘finally’ block?
Ans : Finally block will execute whether or not an exception is thrown. If an exception is thrown, the finally block will execute even if no catch statement match the exception. Any time a method is about to return to the caller from inside try/catch block, via an uncaught exception or an explicit return statement, the finally clause is also execute.
5) Can we have catch block with out try block? If so when?
Ans : No. Try/Catch or Try/finally form a unit.
6) What is the difference between the following statements?
Catch (Exception e),
Catch (Error err),
Catch (Throwable t)
Ans :
7) What will happen to the Exception object after exception handling?
Ans : It will go for Garbage Collector. And frees the memory.
8) How many Exceptions we can define in ‘throws’ clause?
Ans : We can define multiple exceptions in throws clause.
Signature is..
type method-name (parameter-list) throws exception-list
9) The finally block is executed when an exception is thrown, even if no catch matches it.
True/False
Ans : True
10) The subclass exception should precede the base class exception when used within the catch clause.
True/False
Ans : True
11) Exceptions can be caught or rethrown to a calling method.
True/False
Ans : True
12) The statements following the throw keyword in a program are not executed.
True/False
Ans : True
13) The toString ( ) method in the user-defined exception class is overridden.
True/False
Ans : True
MULTI THREADING
1) What are the two types of multitasking?
Ans : 1.process-based
2.Thread-based
2) What are the two ways to create the thread?
Ans : 1.by implementing Runnable
2.by extending Thread
3) What is the signature of the constructor of a thread class?
Ans : Thread(Runnable threadob,String threadName)
4) What are all the methods available in the Runnable Interface?
Ans : run()
5) What is the data type for the method isAlive() and this method is
available in which class?
Ans : boolean, Thread
6) What are all the methods available in the Thread class?
Ans : 1.isAlive()
2.join()
3.resume()
4.suspend()
5.stop()
6.start()
7.sleep()
8.destroy()
7) What are all the methods used for Inter Thread communication and what is the class in which these methods are defined?
Ans :1. wait(),notify() & notifyall()
2. Object class
8) What is the mechanisam defind by java for the Resources to be used by only one Thread at a time?
Ans : Synchronisation
9) What is the procedure to own the moniter by many threads?
Ans : not possible
10) What is the unit for 1000 in the below statement?
ob.sleep(1000)
Ans : long milliseconds
11) What is the data type for the parameter of the sleep() method?
Ans : long
12) What are all the values for the following level?
max-priority
min-priority
normal-priority
Ans : 10,1,5
13) What is the method available for setting the priority?
Ans : setPriority()
14) What is the default thread at the time of starting the program?
Ans : main thread
15) The word synchronized can be used with only a method.
True/ False
Ans : False
16) Which priority Thread can prompt the lower primary Thread?
Ans : Higher Priority
17) How many threads at a time can access a monitor?
Ans : one
18) What are all the four states associated in the thread?
Ans : 1. new 2. runnable 3. blocked 4. dead
19) The suspend()method is used to teriminate a thread?
True /False
Ans : False
20) The run() method should necessary exists in clases created as subclass of thread?
True /False
Ans : True
21) When two threads are waiting on each other and can't proceed the programe is said to be in a deadlock?
True/False
Ans : True
22) Which method waits for the thread to die ?
Ans : join() method
23) Which of the following is true?
1) wait(),notify(),notifyall() are defined as final & can be called only from with in a synchronized method
2) Among wait(),notify(),notifyall() the wait() method only throws IOException
3) wait(),notify(),notifyall() & sleep() are methods of object class
1
2
3
1 & 2
1,2 & 3
Ans : D
24) Garbage collector thread belongs to which priority?
Ans : low-priority
25) What is meant by timeslicing or time sharing?
Ans : Timeslicing is the method of allocating CPU time to individual threads in a priority schedule.
26) What is meant by daemon thread? In java runtime, what is it's role?
Ans : Daemon thread is a low priority thread which runs intermittently in the background doing the garbage collection operation for the java runtime system.
Inheritance
1) What is the difference between superclass & subclass?
Ans : A super class is a class that is inherited whereas subclass is a class that does the inheriting.
2) Which keyword is used to inherit a class?
Ans : extends
3) Subclasses methods can access superclass members/ attributes at all times?
True/False
Ans : False
4) When can subclasses not access superclass members?
Ans : When superclass is declared as private.
5) Which class does begin Java class hierarchy?
Ans : Object class
6) Object class is a superclass of all other classes?
True/False
Ans : True
7) Java supports multiple inheritance?
True/False
Ans : False
8) What is inheritance?
Ans : Deriving an object from an existing class. In the other words, Inheritance is the process of inheriting all the features from a class
9) What are the advantages of inheritance?
Ans : Reusability of code and accessibility of variables and methods of the superclass by subclasses.
10) Which method is used to call the constructors of the superclass from the subclass?
Ans : super(argument)
11) Which is used to execute any method of the superclass from the subclass?
Ans : super.method-name(arguments)
12) Which methods are used to destroy the objects created by the constructor methods?
Ans : finalize()
13) What are abstract classes?
Ans : Abstract classes are those for which instances can’t be created.
14) What must a class do to implement an interface?
Ans: It must provide all of the methods in the interface and identify the interface in its implements clause.
15) Which methods in the Object class are declared as final?
Ans : getClass(), notify(), notifyAll(), and wait()
16) Final methods can be overridden.
True/False
Ans : False
17) Declaration of methods as final results in faster execution of the program?
True/False
Ans: True
18) Final variables should be declared in the beginning?
True/False
Ans : True
19) Can we declare variable inside a method as final variables? Why?
Ans : Cannot because, local variable cannot be declared as final variables.
20) Can an abstract class may be final?
Ans : An abstract class may not be declared as final.
21) Does a class inherit the constructors of it's super class?
Ans: A class does not inherit constructors from any of it's super classes.
22) What restrictions are placed on method overloading?
Ans: Two methods may not have the same name and argument list but different return types.
23) What restrictions are placed on method overriding?
Ans : Overridden methods must have the same name , argument list , and return type. The overriding method may not limit the access of the method it overridees.The overriding method may not throw any exceptions that may not be thrown by the overridden method.
24) What modifiers may be used with an inner class that is a member of an outer class?
Ans : a (non-local) inner class may be declared as public, protected, private, static, final or abstract.
25) How this() is used with constructors?
Ans: this() is used to invoke a constructor of the same class
26) How super() used with constructors?
Ans : super() is used to invoke a super class constructor
27) Which of the following statements correctly describes an interface?
a)It's a concrete class
b)It's a superclass
c)It's a type of abstract class
Ans: c
28) An interface contains __ methods
a)Non-abstract
b)Implemented
c)unimplemented
Ans:c
STRING HANDLING
Which package does define String and StringBuffer classes?
Ans : java.lang package.
Which method can be used to obtain the length of the String?
Ans : length( ) method.
How do you concatenate Strings?
Ans : By using " + " operator.
Which method can be used to compare two strings for equality?
Ans : equals( ) method.
Which method can be used to perform a comparison between strings that ignores case differences?
Ans : equalsIgnoreCase( ) method.
What is the use of valueOf( ) method?
Ans : valueOf( ) method converts data from its internal format into a human-readable form.
What are the uses of toLowerCase( ) and toUpperCase( ) methods?
Ans : The method toLowerCase( ) converts all the characters in a string from uppercase to
lowercase.
The method toUpperCase( ) converts all the characters in a string from lowercase to
uppercase.
Which method can be used to find out the total allocated capacity of a StrinBuffer?
Ans : capacity( ) method.
Which method can be used to set the length of the buffer within a StringBuffer object?
Ans : setLength( ).
What is the difference between String and StringBuffer?
Ans : String objects are constants, whereas StringBuffer objects are not.
String class supports constant strings, whereas StringBuffer class supports growable, modifiable strings.
What are wrapper classes?
Ans : Wrapper classes are classes that allow primitive types to be accessed as objects.
Which of the following is not a wrapper class?
String
Integer
Boolean
Character
Ans : a.
What is the output of the following program?
public class Question {
public static void main(String args[]) {
String s1 = "abc";
String s2 = "def";
String s3 = s1.concat(s2.toUpperCase( ) );
System.out.println(s1+s2+s3);
}
}
abcdefabcdef
abcabcDEFDEF
abcdefabcDEF
None of the above
ANS : c.
Which of the following methods are methods of the String class?
delete( )
append( )
reverse( )
replace( )
Ans : d.
Which of the following methods cause the String object referenced by s to be changed?
s.concat( )
s.toUpperCase( )
s.replace( )
s.valueOf( )
Ans : a and b.
String is a wrapper class?
True
False
Ans : b.
17) If you run the code below, what gets printed out?
String s=new String("Bicycle");
int iBegin=1;
char iEnd=3;
System.out.println(s.substring(iBegin,iEnd));
Bic
ic
c) icy
d) error: no method matching substring(int,char)
Ans : b.
18) Given the following declarations
String s1=new String("Hello")
String s2=new String("there");
String s3=new String();
Which of the following are legal operations?
s3=s1 + s2;
s3=s1 - s2;
c) s3=s1 & s2
d) s3=s1 && s2
Ans : a.
19) Which of the following statements are true?
The String class is implemented as a char array, elements are addressed using the stringname[] convention
b) Strings are a primitive type in Java that overloads the + operator for concatenation
c) Strings are a primitive type in Java and the StringBuffer is used as the matching wrapper type
d) The size of a string can be retrieved using the length property.
Ans : b.
EXPLORING JAVA.LANG
java.lang package is automatically imported into all programs.
True
False
Ans : a
What are the interfaces defined by java.lang?
Ans : Cloneable, Comparable and Runnable.
What are the constants defined by both Flaot and Double classes?
Ans : MAX_VALUE,
MIN_VALUE,
NaN,
POSITIVE_INFINITY,
NEGATIVE_INFINITY and
TYPE.
What are the constants defined by Byte, Short, Integer and Long?
Ans : MAX_VALUE,
MIN_VALUE and
TYPE.
What are the constants defined by both Float and Double classes?
Ans : MAX_RADIX,
MIN_RADIX,
MAX_VALUE,
MIN_VALUE and
TYPE.
What is the purpose of the Runtime class?
Ans : The purpose of the Runtime class is to provide access to the Java runtime system.
What is the purpose of the System class?
Ans : The purpose of the System class is to provide access to system resources.
Which class is extended by all other classes?
Ans : Object class is extended by all other classes.
Which class can be used to obtain design information about an object?
Ans : The Class class can be used to obtain information about an object’s design.
Which method is used to calculate the absolute value of a number?
Ans : abs( ) method.
What are E and PI?
Ans : E is the base of the natural logarithm and PI is the mathematical value pi.
Which of the following classes is used to perform basic console I/O?
System
SecurityManager
Math
Runtime
Ans : a.
Which of the following are true?
The Class class is the superclass of the Object class.
The Object class is final.
The Class class can be used to load other classes.
The ClassLoader class can be used to load other classes.
Ans : c and d.
Which of the following methods are methods of the Math class?
absolute( )
log( )
cosine( )
sine( )
Ans : b.
Which of the following are true about the Error and Exception classes?
Both classes extend Throwable.
The Error class is final and the Exception class is not.
The Exception class is final and the Error is not.
Both classes implement Throwable.
Ans : a.
Which of the following are true?
The Void class extends the Class class.
The Float class extends the Double class.
The System class extends the Runtime class.
The Integer class extends the Number class.
Ans : d.
17) Which of the following will output -4.0
System.out.println(Math.floor(-4.7));
System.out.println(Math.round(-4.7));
System.out.println(Math.ceil(-4.7));
d) System.out.println(Math.Min(-4.7));
Ans : c.
18) Which of the following are valid statements
a) public class MyCalc extends Math
b) Math.max(s);
c) Math.round(9.99,1);
d) Math.mod(4,10);
e) None of the above.
Ans : e.
19) What will happen if you attempt to compile and run the following code?
Integer ten=new Integer(10);
Long nine=new Long (9);
System.out.println(ten + nine);
int i=1;
System.out.println(i + ten);
19 followed by 20
19 followed by 11
Error: Can't convert java lang Integer
d) 10 followed by 1
Ans : c.
INPUT / OUTPUT : EXPLORING JAVA.IO
What is meant by Stream and what are the types of Streams and classes of the Streams?
Ans : A Stream is an abstraction that either produces or consumes information.
There are two types of Streams. They are:
Byte Streams : Byte Streams provide a convenient means for handling input and output of bytes.
Character Streams : Character Streams provide a convenient means for handling input and output of characters.
Byte Stream classes : Byte Streams are defined by using two abstract classes. They are:InputStream and OutputStream.
Character Stream classes : Character Streams are defined by using two abstract classes. They are : Reader and Writer.
Which of the following statements are true?
UTF characters are all 8-bits.
UTF characters are all 16-bits.
UTF characters are all 24-bits.
Unicode characters are all 16-bits.
Bytecode characters are all 16-bits.
Ans : d.
Which of the following statements are true?
When you construct an instance of File, if you do not use the filenaming semantics of the local machine, the constructor will throw an IOException.
When you construct an instance of File, if the corresponding file does not exist on the local file system, one will be created.
When an instance of File is garbage collected, the corresponding file on the local file system is deleted.
None of the above.
Ans : a,b and c.
The File class contains a method that changes the current working directory.
True
False
Ans : b.
It is possible to use the File class to list the contents of the current working directory.
True
False
Ans : a.
Readers have methods that can read and return floats and doubles.
True
False
Ans : b.
You execute the code below in an empty directory. What is the result?
File f1 = new File("dirname");
File f2 = new File(f1, "filename");
A new directory called dirname is created in the current working directory.
A new directory called dirname is created in the current working directory. A new file called filename is created in directory dirname.
A new directory called dirname and a new file called filename are created, both in the current working directory.
A new file called filename is created in the current working directory.
No directory is created, and no file is created.
Ans : e.
What is the difference between the Reader/Writer class hierarchy and the
InputStream/OutputStream class hierarchy?
Ans : The Reader/Writer class hierarchy is character-oriented and the InputStream/OutputStream class hierarchy is byte-oriented.
What is an I/O filter?
Ans : An I/O filter is an object that reads from one stream and writes to another, usually altering the data in some way as it is passed from one stream to another.
What is the purpose of the File class?
Ans : The File class is used to create objects that provide access to the files and directories of a local file system.
What interface must an object implement before it can be written to a stream as an object?
Ans : An object must implement the Serializable or Externalizable interface before it can be written to a stream as an object.
What is the difference between the File and RandomAccessFile classes?
Ans : The File class encapsulates the files and directories of the local file system. The RandomAccessFile class provides the methods needed to directly access data contained in any part of a file.
What class allows you to read objects directly from a stream?
Ans : The ObjectInputStream class supports the reading of objects from input streams.
What value does read( ) return when it has reached the end of a file?
Ans : The read( ) method returns – 1 when it has reached the end of a file.
What value does readLine( ) return when it has reached the end of a file?
Ans : The readLine( ) method returns null when it has reached the end of a file.
How many bits are used to represent Unicode, ASCII, UTF-16 and UTF-8 characters?
Ans : Unicode requires 16-bits and ASCII requires 8-bits. Although the ASCII character set uses only 1-bits, it is usually represented as 8-bits. UTF-8 represents characters using 8, 16 and 18-bit patterns. UTF-16 uses 16-bit and larger bit patterns.
Which of the following are true?
The InputStream and OutputStream classes are byte-oriented.
The ObjectInputStream and ObjectOutputStream do not support serialized object input and output.
The Reader and Writer classes are character-oriented.
The Reader and Writer classes are the preferred solution to serialized object output.
Ans : a and c.
Which of the following are true about I/O filters?
Filters are supported on input, but not on output.
Filters are supported by the InputStream/OutputStream class hierarchy, but not by the Reader/Writer class hierarchy.
Filters read from one stream and write to another.
A filter may alter data that is read from one stream and written to another.
Ans : c and d.
Which of the following are true?
Any Unicode character is represented using 16-bits.
7-bits are needed to represent any ASCII character.
UTF-8 characters are represented using only 8-bits.
UTF-16 characters are represented using only 16-bits.
Ans : a and b.
Which of the following are true?
The Serializable interface is used to identify objects that may be written to an output stream.
The Externalizable interface is implemented by classes that control the way in which their objects are serialized.
The Serializable interface extends the Externalizable interface.
The Externalizable interface extends the Serializable interface.
Ans : a, b and d.
Which of the following are true about the File class?
A File object can be used to change the current working directory.
A File object can be used to access the files in the current directory.
When a File object is created, a corresponding directory or file is created in the local file system.
File objects are used to access files and directories on the local file system.
File objects can be garbage collected.
When a File object is garbage collected, the corresponding file or directory is deleted.
Ans : b, d and e.
How do you create a Reader object from an InputStream object?
Use the static createReader( ) method of InputStream class.
Use the static createReader( ) method of Reader class.
Create an InputStreamReader object, passing the InputStream object as an argument to the InputStreamReader constructor.
Create an OutputStreamReader object, passing the InputStream object as an argument to the OutputStreamReader constructor.
Ans : c.
Which of the following are true?
Writer classes can be used to write characters to output streams using different character encodings.
Writer classes can be used to write Unicode characters to output streams.
Writer classes have methods that support the writing of the values of any Java primitive type to output streams.
Writer classes have methods that support the writing of objects to output streams.
Ans : a and b.
The isFile( ) method returns a boolean value depending on whether the file object is a file or a directory.
True.
False.
Ans : a.
Reading or writing can be done even after closing the input/output source.
True.
False.
Ans : b.
The ________ method helps in clearing the buffer.
Ans : flush( ).
The System.err method is used to print error message.
True.
False.
Ans : a.
What is meant by StreamTokenizer?
Ans : StreamTokenizer breaks up InputStream into tokens that are delimited by sets of characters.
It has the constructor : StreamTokenizer(Reader inStream).
Here inStream must be some form of Reader.
What is Serialization and deserialization?
Ans : Serialization is the process of writing the state of an object to a byte stream.
Deserialization is the process of restoring these objects.
30) Which of the following can you perform using the File class?
a) Change the current directory
b) Return the name of the parent directory
c) Delete a file
d) Find if a file contains text or binary information
Ans : b and c.
31)How can you change the current working directory using an instance of the File class called FileName?
FileName.chdir("DirName").
FileName.cd("DirName").
FileName.cwd("DirName").
The File class does not support directly changing the current directory.
Ans : d.
EVENT HANDLING
The event delegation model, introduced in release 1.1 of the JDK, is fully compatible with the
event model.
True
False
Ans : b.
A component subclass that has executed enableEvents( ) to enable processing of a certain kind of event cannot also use an adapter as a listener for the same kind of event.
True
False
Ans : b.
What is the highest-level event class of the event-delegation model?
Ans : The java.util.eventObject class is the highest-level class in the event-delegation hierarchy.
What interface is extended by AWT event listeners?
Ans : All AWT event listeners extend the java.util.EventListener interface.
What class is the top of the AWT event hierarchy?
Ans : The java.awt.AWTEvent class is the highest-level class in the AWT event class hierarchy.
What event results from the clicking of a button?
Ans : The ActionEvent event is generated as the result of the clicking of a button.
What is the relationship between an event-listener interface and an event-adapter class?
Ans : An event-listener interface defines the methods that must be implemented by an event
handler for a particular kind of event.
An event adapter provides a default implementation of an event-listener interface.
In which package are most of the AWT events that support the event-delegation model defined?
Ans : Most of the AWT–related events of the event-delegation model are defined in the
java.awt.event package. The AWTEvent class is defined in the java.awt package.
What is the advantage of the event-delegation model over the earlier event-inheritance model?
Ans : The event-delegation has two advantages over the event-inheritance model. They are :
It enables event handling by objects other than the ones that generate the events. This
allows a clean separation between a component’s design and its use.
It performs much better in applications where many events are generated. This
performance improvement is due to the fact that the event-delegation model does not
have to repeatedly process unhandled events, as is the case of the event-inheritance
model.
What is the purpose of the enableEvents( ) method?
Ans :The enableEvents( ) method is used to enable an event for a particular object.
Which of the following are true?
The event-inheritance model has replaced the event-delegation model.
The event-inheritance model is more efficient than the event-delegation model.
The event-delegation model uses event listeners to define the methods of event-handling classes.
The event-delegation model uses the handleEvent( ) method to support event handling.
Ans : c.
Which of the following is the highest class in the event-delegation model?
java.util.EventListener
java.util.EventObject
java.awt.AWTEvent
java.awt.event.AWTEvent
Ans : b.
When two or more objects are added as listeners for the same event, which listener is first invoked to handle the event?
The first object that was added as listener.
The last object that was added as listener.
There is no way to determine which listener will be invoked first.
It is impossible to have more than one listener for a given event.
Ans : c.
Which of the following components generate action events?
Buttons
Labels
Check boxes
Windows
Ans : a.
Which of the following are true?
A TextField object may generate an ActionEvent.
A TextArea object may generate an ActionEvent.
A Button object may generate an ActionEvent.
A MenuItem object may generate an ActionEvent.
Ans : a,c and d.
Which of the following are true?
The MouseListener interface defines methods for handling mouse clicks.
The MouseMotionListener interface defines methods for handling mouse clicks.
The MouseClickListener interface defines methods for handling mouse clicks.
The ActionListener interface defines methods for handling the clicking of a button.
Ans : a and d.
Suppose that you want to have an object eh handle the TextEvent of a TextArea object t. How should you add eh as the event handler for t?
t.addTextListener(eh);
eh.addTextListener(t);
addTextListener(eh.t);
addTextListener(t,eh);
Ans : a.
What is the preferred way to handle an object’s events in Java 2?
Override the object’s handleEvent( ) method.
Add one or more event listeners to handle the events.
Have the object override its processEvent( ) methods.
Have the object override its dispatchEvent( ) methods.
Ans : b.
Which of the following are true?
A component may handle its own events by adding itself as an event listener.
A component may handle its own events by overriding its event-dispatching method.
A component may not handle oits own events.
A component may handle its own events only if it implements the handleEvent( ) method.
Ans : a and b.
APPLETS
What is an Applet? Should applets have constructors?
Ans : Applet is a dynamic and interactive program that runs inside a Web page
displayed by a Java capable browser. We don’t have the concept of Constructors in Applets.
How do we read number information from my applet’s parameters, given that Applet’s getParameter() method returns a string?
Ans : Use the parseInt() method in the Integer Class, the Float(String) constructor in the
Class Float, or the Double(String) constructor in the class Double.
How can I arrange for different applets on a web page to communicate with each other?
Ans : Name your applets inside the Applet tag and invoke AppletContext’s getApplet()
method in your applet code to obtain references to the other applets on the page.
How do I select a URL from my Applet and send the browser to that page?
Ans : Ask the applet for its applet context and invoke showDocument() on that context object.
Eg. URL targetURL;
String URLString
AppletContext context = getAppletContext();
try{
targetUR L = new URL(URLString);
} catch (Malformed URLException e){
// Code for recover from the exception
}
context. showDocument (targetURL);
Can applets on different pages communicate with each other?
Ans : No. Not Directly. The applets will exchange the information at one meeting place
either on the local file system or at remote system.
How do Applets differ from Applications?
Ans : Appln: Stand Alone
Applet: Needs no explicit installation on local m/c.
Appln: Execution starts with main() method.
Applet: Execution starts with init() method.
Appln: May or may not be a GUI
Applet: Must run within a GUI (Using AWT)
How do I determine the width and height of my application?
Ans : Use the getSize() method, which the Applet class inherits from the Component
class in the Java.awt package. The getSize() method returns the size of the applet as
a Dimension object, from which you extract separate width, height fields.
Eg. Dimension dim = getSize ();
int appletwidth = dim.width ();
8) What is AppletStub Interface?
Ans : The applet stub interface provides the means by which an applet and the browser communicate. Your code will not typically implement this interface.
It is essential to have both the .java file and the .html file of an applet in the same
directory.
True.
False.
Ans : b.
The <PARAM> tag contains two attributes namely _________ and _______.
Ans : Name , value.
Passing values to parameters is done in the _________ file of an applet.
Ans : .html.
12) What tags are mandatory when creating HTML to display an applet
name, height, width
code, name
codebase, height, width
d) code, height, width
Ans : d.
Applet’s getParameter( ) method can be used to get parameter values.
True.
False.
Ans : a.
What are the Applet’s Life Cycle methods? Explain them?
Ans : init( ) method - Can be called when an applet is first loaded.
start( ) method - Can be called each time an applet is started.
paint( ) method - Can be called when the applet is minimized or refreshed.
stop( ) method - Can be called when the browser moves off the applet’s page.
destroy( ) method - Can be called when the browser is finished with the applet.
What are the Applet’s information methods?
Ans : getAppletInfo( ) method : Returns a string describing the applet, its author ,copy
right information, etc.
getParameterInfo( ) method : Returns an array of string describing the applet’s parameters.
All Applets are subclasses of Applet.
True.
False.
Ans : a.
All Applets must import java.applet and java.awt.
True.
False.
Ans : a.
What are the steps involved in Applet development?
Ans : a) Edit a Java source file,
b) Compile your program and
c) Execute the appletviewer, specifying the name of your applet’s source file.
Applets are executed by the console based Java run-time interpreter.
True.
False.
Ans : b.
Which classes and interfaces does Applet class consist?
Ans : Applet class consists of a single class, the Applet class and three interfaces: AppletContext,
AppletStub and AudioClip.
What is the sequence for calling the methods by AWT for applets?
Ans : When an applet begins, the AWT calls the following methods, in this sequence.
init( )
start( )
paint( )
When an applet is terminated, the following sequence of method cals takes place :
stop( )
destroy( )
Which method is used to output a string to an applet?
Ans : drawString ( ) method.
Every color is created from an RGB value.
True.
False
Ans : a.
AWT : WINDOWS, GRAPHICS AND FONTS
How would you set the color of a graphics context called g to cyan?
g.setColor(Color.cyan);
g.setCurrentColor(cyan);
g.setColor("Color.cyan");
g.setColor("cyan’);
g.setColor(new Color(cyan));
Ans : a.
The code below draws a line. What color is the line?
g.setColor(Color.red.green.yellow.red.cyan);
g.drawLine(0, 0, 100,100);
Red
Green
Yellow
Cyan
Black
Ans : d.
What does the following code draw?
g.setColor(Color.black);
g.drawLine(10, 10, 10, 50);
g.setColor(Color.RED);
g.drawRect(100, 100, 150, 150);
A red vertical line that is 40 pixels long and a red square with sides of 150 pixels
A black vertical line that is 40 pixels long and a red square with sides of 150 pixels
A black vertical line that is 50 pixels long and a red square with sides of 150 pixels
A red vertical line that is 50 pixels long and a red square with sides of 150 pixels
A black vertical line that is 40 pixels long and a red square with sides of 100 pixel
Ans : b.
Which of the statements below are true?
A polyline is always filled.
b) A polyline can not be filled.
c) A polygon is always filled.
d) A polygon is always closed
e) A polygon may be filled or not filled
Ans : b, d and e.
What code would you use to construct a 24-point bold serif font?
new Font(Font.SERIF, 24,Font.BOLD);
new Font("SERIF", 24, BOLD");
new Font("BOLD ", 24,Font.SERIF);
new Font("SERIF", Font.BOLD,24);
new Font(Font.SERIF, "BOLD", 24);
Ans : d.
What does the following paint( ) method draw?
Public void paint(Graphics g) {
g.drawString("question #6",10,0);
}
The string "question #6", with its top-left corner at 10,0
A little squiggle coming down from the top of the component, a little way in from the left edge
Ans : b.
What does the following paint( ) method draw?
Public void paint(Graphics g) {
g.drawString("question #6",10,0);
}
A circle at (100, 100) with radius of 44
A circle at (100, 44) with radius of 100
A circle at (100, 44) with radius of 44
The code does not compile
Ans : d.
8)What is relationship between the Canvas class and the Graphics class?
Ans : A Canvas object provides access to a Graphics object via its paint( ) method.
What are the Component subclasses that support painting.
Ans : The Canvas, Frame, Panel and Applet classes support painting.
What is the difference between the paint( ) and repaint( ) method?
Ans : The paint( ) method supports painting via a Graphics object. The repaint( ) method is used
to cause paint( ) to be invoked by the AWT painting method.
What is the difference between the Font and FontMetrics classes?
Ans : The FontMetrics class is used to define implementation-specific properties, such as ascent
and descent, of a Font object.
Which of the following are passed as an argument to the paint( ) method?
A Canvas object
A Graphics object
An Image object
A paint object
Ans : b.
Which of the following methods are invoked by the AWT to support paint and repaint operations?
paint( )
repaint( )
draw( )
redraw( )
Ans : a.
Which of the following classes have a paint( ) method?
Canvas
Image
Frame
Graphics
Ans : a and c.
Which of the following are methods of the Graphics class?
drawRect( )
drawImage( )
drawPoint( )
drawString( )
Ans : a, b and d.
Which Font attributes are available through the FontMetrics class?
ascent
leading
case
height
Ans : a, b and d.
Which of the following are true?
The AWT automatically causes a window to be repainted when a portion of a window has been minimized and then maximized.
The AWT automatically causes a window to be repainted when a portion of a window has been covered and then uncovered.
The AWT automatically causes a window to be repainted when application data is changed.
The AWT does not support repainting operations.
Ans : a and b.
Which method is used to size a graphics object to fit the current size of the window?
Ans : getSize( ) method.
What are the methods to be used to set foreground and background colors?
Ans : setForeground( ) and setBackground( ) methods.
19) You have created a simple Frame and overridden the paint method as follows
public void paint(Graphics g){
g.drawString("Dolly",50,10);
}
What will be the result when you attempt to compile and run the program?
The string "Dolly" will be displayed at the centre of the frame
b) An error at compilation complaining at the signature of the paint method
c) The lower part of the word Dolly will be seen at the top of the form, with the top hidden.
d) The string "Dolly" will be shown at the bottom of the form
Ans : c.
20) Where g is a graphics instance what will the following code draw on the screen.
g.fillArc(45,90,50,50,90,180);
a) An arc bounded by a box of height 45, width 90 with a centre point of 50,50, starting
at an angle of 90 degrees traversing through 180 degrees counter clockwise.
b) An arc bounded by a box of height 50, width 50, with a centre point of 45,90 starting
at an angle of 90 degrees traversing through 180 degrees clockwise.
c) An arc bounded by a box of height 50, width 50, with a top left at coordinates of 45,
90, starting at 90 degrees and traversing through 180 degrees counter clockwise.
d) An arc starting at 45 degrees, traversing through 90 degrees clockwise bounded by a
box of height 50, width 50 with a centre point of 90, 180.
Ans : c.
21) Given the following code
import java.awt.*;
public class SetF extends Frame{
public static void main(String argv[]){
SetF s = new SetF();
s.setSize(300,200);
s.setVisible(true);
}
}
How could you set the frame surface color to pink
a)s.setBackground(Color.pink);
b)s.setColor(PINK);
c)s.Background(pink);
d)s.color=Color.pink
Ans : a.
AWT: CONTROLS, LAYOUT MANAGERS AND MENUS
What is meant by Controls and what are different types of controls?
Ans : Controls are componenets that allow a user to interact with your application.
The AWT supports the following types of controls:
Labels
Push buttons
Check boxes
Choice lists
Lists
Scroll bars
Text components
These controls are subclasses of Component.
You want to construct a text area that is 80 character-widths wide and 10 character-heights tall. What code do you use?
new TextArea(80, 10)
new TextArea(10, 80)
Ans: b.
A text field has a variable-width font. It is constructed by calling new
TextField("iiiii"). What happens if you change the contents of the text field to
"wwwww"? (Bear in mind that is one of the narrowest characters, and w is one of the widest.)
The text field becomes wider.
The text field becomes narrower.
The text field stays the same width; to see the entire contents you will have to scroll by using the ß and à keys.
The text field stays the same width; to see the entire contents you will have to scroll by using the text field’s horizontal scroll bar.
Ans : c.
The CheckboxGroup class is a subclass of the Component class.
True
False
Ans : b.
5) What are the immediate super classes of the following classes?
a) Container class
b) MenuComponent class
c) Dialog class
d) Applet class
e) Menu class
Ans : a) Container - Component
b) MenuComponent - Object
c) Dialog - Window
d) Applet - Panel
e) Menu - MenuItem
6) What are the SubClass of Textcomponent Class?
Ans : TextField and TextArea
7) Which method of the component class is used to set the position and the size of a component?
Ans : setBounds()
8) Which TextComponent method is used to set a TextComponent to the read-only state?
Ans : setEditable()
9) How can the Checkbox class be used to create a radio button?
Ans : By associating Checkbox objects with a CheckboxGroup.
10) What Checkbox method allows you to tell if a Checkbox is checked?
Ans : getState()
11) Which Component method is used to access a component's immediate Container?
getVisible()
getImmediate
getParent()
getContainer
Ans : c.
12) What methods are used to get and set the text label displayed by a Button object?
Ans : getLabel( ) and setLabel( )
13) What is the difference between a Choice and a List?
Ans : A Choice is displayed in a compact form that requires you to pull it down to see the list of available choices. Only one item may be selected from a Choice.
A List may be displayed in such a way that several List items are visible. A List supports the selection of one or more List items.
14) Which Container method is used to cause a container to be laid out and redisplayed?
Ans : validate( )
15) What is the difference between a Scollbar and a Scrollpane?
Ans : A Scrollbar is a Component, but not a Container.
A Scrollpane is a Container and handles its own events and performs its own
scrolling.
16) Which Component subclass is used for drawing and painting?
Ans : Canvas.
17) Which of the following are direct or indirect subclasses of Component?
Button
Label
CheckboxMenuItem
Toolbar
Frame
Ans : a, b and e.
18) Which of the following are direct or indirect subclasses of Container?
Frame
TextArea
MenuBar
FileDialog
Applet
Ans : a,d and e.
19) Which method is used to set the text of a Label object?
setText( )
setLabel( )
setTextLabel( )
setLabelText( )
Ans : a.
20) Which constructor creates a TextArea with 10 rows and 20 columns?
new TextArea(10, 20)
new TextArea(20, 10)
new TextArea(new Rows(10), new columns(20))
new TextArea(200)
Ans : a.
(Usage is TextArea(rows, columns)
21) Which of the following creates a List with 5 visible items and multiple selection enabled?
new List(5, true)
new List(true, 5)
new List(5, false)
new List(false,5)
Ans : a.
[Usage is List(rows, multipleMode)]
22) Which are true about the Container class?
The validate( ) method is used to cause a Container to be laid out and redisplayed.
The add( ) method is used to add a Component to a Container.
The getBorder( ) method returns information about a Container’s insets.
The getComponent( ) method is used to access a Component that is contained in a Container.
Ans : a, b and d.
23) Suppose a Panel is added to a Frame and a Button is added to the Panel. If the Frame’s font is set to 12-point TimesRoman, the Panel’s font is set to 10-point TimesRoman, and the Button’s font is not set, what font will be used to dispaly the Button’s label?
12-point TimesRoman
11-point TimesRoman
10-point TimesRoman
9-point TimesRoman
Ans : c.
A Frame’s background color is set to Color.Yellow, and a Button’s background color is to Color.Blue. Suppose the Button is added to a Panel, which is added to the Frame. What background color will be used with the Panel?
Colr.Yellow
Color.Blue
Color.Green
Color.White
Ans : a.
25) Which method will cause a Frame to be displayed?
show( )
setVisible( )
display( )
displayFrame( )
Ans : a and b.
26) All the componenet classes and container classes are derived from _________ class.
Ans : Object.
27) Which method of the container class can be used to add components to a Panel.
Ans : add ( ) method.
28) What are the subclasses of the Container class?
Ans : The Container class has three major subclasses. They are :
Window
Panel
ScrollPane
29) The Choice component allows multiple selection.
True.
False.
Ans : b.
30) The List component does not generate any events.
True.
False.
Ans : b.
31) Which components are used to get text input from the user.
Ans : TextField and TextArea.
32) Which object is needed to group Checkboxes to make them exclusive?
Ans : CheckboxGroup.
33) Which of the following components allow multiple selections?
Non-exclusive Checkboxes.
Radio buttons.
Choice.
List.
Ans : a and d.
34) What are the types of Checkboxes and what is the difference between them?
Ans : Java supports two types of Checkboxes. They are : Exclusive and Non-exclusive.
In case of exclusive Checkboxes, only one among a group of items can be selected at a time. I f an item from the group is selected, the checkbox currently checked is deselected and the new selection is highlighted. The exclusive Checkboxes are also called as Radio buttons.
The non-exclusive checkboxes are not grouped together and each one can be selected independent of the other.
35) What is a Layout Manager and what are the different Layout Managers available in java.awt and what is the default Layout manager for the panal and the panal subclasses?
Ans: A layout Manager is an object that is used to organize components in a container.
The different layouts available in java.awt are :
FlowLayout, BorderLayout, CardLayout, GridLayout and GridBag Layout.
The default Layout Manager of Panal and Panal sub classes is FlowLayout".
36) Can I exert control over the size and placement of components in my interface?
Ans : Yes.
myPanal.setLayout(null);
myPanal.setbounds(20,20,200,200);
37) Can I add the same component to more than one container?
Ans : No. Adding a component to a container automatically removes it from any previous parent(container).
38) How do I specify where a window is to be placed?
Ans : Use setBounds, setSize, or setLocation methods to implement this.
setBounds(int x, int y, int width, int height)
setBounds(Rectangle r)
setSize(int width, int height)
setSize(Dimension d)
setLocation(int x, int y)
setLocation(Point p)
39) How can we create a borderless window?
Ans : Create an instance of the Window class, give it a size, and show it on the screen.
eg. Frame aFrame = ......
Window aWindow = new Window(aFrame);
aWindow.setLayout(new FlowLayout());
aWindow.add(new Button("Press Me"));
aWindow.getBounds(50,50,200,200);
aWindow.show();
40) Can I create a non-resizable windows? If so, how?
Ans: Yes. By using setResizable() method in class Frame.
41) What is the default Layout Manager for the Window and Window subclasses (Frame,Dialog)?
Ans : BorderLayout().
42) How are the elements of different layouts organized?
Ans : FlowLayout : The elements of a FlowLayout are organized in a top to bottom, left to right fashion.
BorderLayout : The elements of a BorderLayout are organized at the
borders (North, South, East and West) and the center of a
container.
CardLayout : The elements of a CardLayout are stacked, one on top of the other, like a deck of cards.
GridLayout : The elements of a GridLayout are of equal size and are laid out using the square of a grid.
GridBagLayout : The elements of a GridBagLayout are organized according to a grid.However, the elements are of different sizes and may occupy
more than one row or column of the grid. In addition, the rows and columns may have different sizes.
43) Which containers use a BorderLayout as their default layout?
Ans : The Window, Frame and Dialog classes use a BorderLayout as their default layout.
44) Which containers use a FlowLayout as their default layout?
Ans : The Panel and the Applet classes use the FlowLayout as their default layout.
45) What is the preferred size of a component?
Ans : The preferred size of a component size that will allow the component to display normally.
46) Which method is method to set the layout of a container?
startLayout( )
initLayout( )
layoutContainer( )
setLayout( )
Ans : d.
47) Which method returns the preferred size of a component?
getPreferredSize( )
getPreferred( )
getRequiredSize( )
getLayout( )
Ans : a.
48) Which layout should you use to organize the components of a container in a
tabular form?
CardLayout
BorederLayout
FlowLayout
GridLayout
Ans : d.
An application has a frame that uses a Border layout manager. Why is it probably not a good idea to put a vertical scroll bar at North in the frame?
The scroll bar’s height would be its preferred height, which is not likely to be enough.
The scroll bar’s width would be the entire width of the frame, which would be much wider than necessary.
Both a and b.
Neither a nor b. There is no problem with the layout as described.
Ans : c.
What is the default layouts for a applet, a frame and a panel?
Ans : For an applet and a panel, Flow layout is the default layout, whereas Border layout is default layout for a frame.
If a frame uses a Grid layout manager and does not contain any panels, then all the components within the frame are the same width and height.
True
False.
Ans : a.
If a frame uses its default layout manager and does not contain any panels, then all the components within the frame are the same width and height.
True
False.
Ans : b.
With a Border layout manager, the component at Center gets all the space that is left over, after the components at North and South have been considered.
True
False
Ans : b.
An Applet has its Layout Manager set to the default of FlowLayout. What code would be the correct to change to another Layout Manager?
setLayoutManager(new GridLayout());
setLayout(new GridLayout(2,2));
c) setGridLayout(2,2,))
d setBorderLayout();
Ans : b.
55) How do you indicate where a component will be positioned using Flowlayout?
a) North, South,East,West
b) Assign a row/column grid reference
c) Pass a X/Y percentage parameter to the add method
d) Do nothing, the FlowLayout will position the component
Ans :d.
56) How do you change the current layout manager for a container?
a) Use the setLayout method
b) Once created you cannot change the current layout manager of a component
c) Use the setLayoutManager method
d) Use the updateLayout method
Ans :a.
57)When using the GridBagLayout manager, each new component requires a new instance of the GridBagConstraints class. Is this statement true or false?
a) true
b) false
Ans : b.
58) Which of the following statements are true?
a)The default layout manager for an Applet is FlowLayout
b) The default layout manager for an application is FlowLayout
c) A layout manager must be assigned to an Applet before the setSize method is called
d) The FlowLayout manager attempts to honor the preferred size of any components
Ans : a and d.
59) Which method does display the messages whenever there is an item selection or deselection of the CheckboxMenuItem menu?
Ans : itemStateChanged method.
60) Which is a dual state menu item?
Ans : CheckboxMenuItem.
61) Which method can be used to enable/diable a checkbox menu item?
Ans : setState(boolean).
Which of the following may a menu contain?
A separator
A check box
A menu
A button
A panel
Ans : a and c.
Which of the following may contain a menu bar?
A panel
A frame
An applet
A menu bar
A menu
Ans : b
64) What is the difference between a MenuItem and a CheckboxMenuItem?
Ans : The CheckboxMenuItem class extends the MenuItem class to support a menu item
that may be checked or unchecked.
65) Which of the following are true?
A Dialog can have a MenuBar.
MenuItem extends Menu.
A MenuItem can be added to a Menu.
A Menu can be added to a Menu.
Ans : c and d.
Which colour is used to indicate instance methods in the standard "javadoc" format documentation:
1) blue
2) red
3) purple
4) orange
Answer : 2
explain
In JDK 1.1 the variabels, methods and constructors are colour coded to simplifytheir identification.
endExplain
What is the correct ordering for the import, class and package declarations when found in a single file?
1) package, import, class
2) class, import, package
3) import, package, class
4) package, class, import
Answer : 1
explain
This is my explanation for question 2
endExplain
Which methods can be legally applied to a string object?
(Multiple)
1) equals(String)
2) equals(Object)
3) trim()
4) round()
5) toString()
Answer : 1,2,3,5
What is the parameter specification for the public static void main method?
(multiple)
1) String args []
2) String [] args
3) Strings args []
4) String args
Answer : 1,2
What does the zeroth element of the string array passed to the public static void main method contain?
(multiple)
1) The name of the program
2) The number of arguments
3) The first argument if one is present
Answer : 3
Which of the following are Java keywords?
(multiple)
1) goto
2) malloc
3) extends
4) FALSE
Answer : 3
What will be the result of compiling the following code:
public class Test {
public static void main (String args []) {
int age;
age = age + 1;
System.out.println("The age is " + age);
}
}
1) Compiles and runs with no output
2) Compiles and runs printing out The age is 1
3) Compiles but generates a runtime error
4) Does not compile
5) Compiles but generates a compile time error
Answer : 4
Which of these is the correct format to use to create the literal char value a?
(multiple)
1) 'a'
2) "a"
3) new Character(a)
4) \000a
Answer : 1
What is the legal range of a byte integral type?
1) 0 - 65, 535
2) (-128) - 127
3) (-32,768) - 32,767
4) (-256) - 255
Answer : 2
Which of the following is illegal:
1) int i = 32;
2) float f = 45.0;
3) double d = 45.0;
Answer 2
What will be the result of compiling the following code:
public class Test {
static int age;
public static void main (String args []) {
age = age + 1;
System.out.println("The age is " + age);
}
}
1) Compiles and runs with no output
2) Compiles and runs printing out The age is 1
3) Compiles but generates a runtime error
4) Does not compile
5) Compiles but generates a compile time error
Answer : 2
Which of the following are correct?
(multiple)
1) 128 >> 1 gives 64
2) 128 >>> 1 gives 64
3) 128 >> 1 gives -64
4) 128 >>> 1 gives -64
Answer : 1
Which of the following return true?
(multiple)
1) "john" == new String("john")
2) "john".equals("john")
3) "john" = "john"
4) "john".equals(new Button("john"))
Answer : 2
Which of the following do not lead to a runtime error?
(multiple)
1) "john" + " was " + " here"
2) "john" + 3
3) 3 + 5
4) 5 + 5.5
answer 1,2,3,4
Which of the following are so called "short circuit" logical operators?
(multiple)
1) &
2) ||
3) &&
4) |
Answer : 2,3
Which of the following are acceptable?
(multiple)
1) Object o = new Button("A");
2) Boolean flag = true;
3) Panel p = new Frame();
4) Frame f = new Panel();
5) Panel p = new Applet();
Answer : 1,5
What is the result of compiling and running the following code:
public class Test {
static int total = 10;
public static void main (String args []) {
new Test();
}
public Test () {
System.out.println("In test");
System.out.println(this);
int temp = this.total;
if (temp > 5) {
System.out.println(temp);
}
}
}
(multiple)
1) The class will not compile
2) The compiler reports and error at line 2
3) The compiler reports an error at line 9
4) The value 10 is one of the elements printed to the standard output
5) The class compiles but generates a runtime error
Answer : 4
Which of the following is correct:
1) String temp [] = new String {"j" "a" "z"};
2) String temp [] = { "j " " b" "c"};
3) String temp = {"a", "b", "c"};
4) String temp [] = {"a", "b", "c"};
Answer 4
What is the correct declaration of an abstract method that is intended to be public:
1) public abstract void add();
2) public abstract void add() {}
3) public abstract add();
4) public virtual add();
Answer : 1
Under what situations do you obtain a default constructor?
1) When you define any class
2) When the class has no other constructors
3) When you define at least one constructor
Answer : 2
Which of the following can be used to define a constructor for this class, given the following code:
public class Test {
...
}
1) public void Test() {...}
2) public Test() {...}
3) public static Test() {...}
4) public static void Test() {...}
Answer : 2
Which of the following are acceptable to the Java compiler:
(multiple)
1) if (2 == 3) System.out.println("Hi");
2) if (2 = 3) System.out.println("Hi");
3) if (true) System.out.println("Hi");
4) if (2 != 3) System.out.println("Hi");
5) if (aString.equals("hello")) System.out.println("Hi");
Answer : 1,3,4,5
Assuming a method contains code which may raise an Exception (but not a RuntimeException), what is the correct way for a method to indicate that it expects the caller to handle that exception:
1) throw Exception
2) throws Exception
3) new Exception
4) Don't need to specify anything
Answer : 2
What is the result of executing the following code, using the parameters 4 and 0:
public void divide(int a, int b) {
try {
int c = a / b;
} catch (Exception e) {
System.out.print("Exception ");
} finally {
System.out.println("Finally");
}
1) Prints out: Exception Finally
2) Prints out: Finally
3) Prints out: Exception
4) No output
Answer : 1
Which of the following is a legal return type of a method overloading the following method:
public void add(int a) {...}
1) void
2) int
3) Can be anything
Answer : 3
Which of the following statements is correct for a method which is overriding the following method:
public void add(int a) {...}
1) the overriding method must return void
2) the overriding method must return int
3) the overriding method can return whatever it likes
Answer : 1
Given the following classes defined in separate files, what will be the effect of compiling and running this class Test?
class Vehicle {
public void drive() {
System.out.println("Vehicle: drive");
}
}
class Car extends Vehicle {
public void drive() {
System.out.println("Car: drive");
}
}
public class Test {
public static void main (String args []) {
Vehicle v;
Car c;
v = new Vehicle();
c = new Car();
v.drive();
c.drive();
v = c;
v.drive();
}
}
1) Generates a Compiler error on the statement v= c;
2) Generates runtime error on the statement v= c;
3) Prints out:
Vehicle: drive
Car: drive
Car: drive
4) Prints out:
Vehicle: drive
Car: drive
Vehicle: drive
Answer : 3
Where in a constructor, can you place a call to a constructor defined in the super class?
1) Anywhere
2) The first statement in the constructor
3) The last statement in the constructor
4) You can't call super in a constructor
Answer : 2
Which variables can an inner class access from the class which encapsulates it?
(multiple)
1) All static variables
2) All final variables
3) All instance variables
4) Only final instance variables
5) Only final static variables
Answer : 1,2,3
What class must an inner class extend:
1) The top level class
2) The Object class
3) Any class or interface
4) It must extend an interface
Answer 3
In the following code, which is the earliest statement, where the object originally held in e, may be garbage collected:
1. public class Test {
2. public static void main (String args []) {
3. Employee e = new Employee("Bob", 48);
4. e.calculatePay();
5. System.out.println(e.printDetails());
6. e = null;
7. e = new Employee("Denise", 36);
8. e.calculatePay();
9. System.out.println(e.printDetails());
10. }
11. }
1) Line 10
2) Line 11
3) Line 7
4) Line 8
5) Never
Answer : 3
What is the name of the interface that can be used to define a class that can execute within its own thread?
1) Runnable
2) Run
3) Threadable
4) Thread
5) Executable
Answer : 1
What is the name of the method used to schedule a thread for execution?
1) init();
2) start();
3) run();
4) resume();
5) sleep();
Answer : 2
Which methods may cause a thread to stop executing?
(multiple)
1) sleep();
2) stop();
3) yield();
4) wait();
5) notify();
6) notifyAll()
7) synchronized()
Answer : 1,2,3,4
Which of the following would create a text field able to display 10 characters (assuming a fixed size font) displaying the initial string "hello":
1) new TextField("hello", 10);
2) new TextField("hello");
3) new textField(10);
4) new TextField();
Answer : 1
Which of the following methods are defined on the Graphics class:
(multiple)
1) drawLine(int, int, int, int)
2) drawImage(Image, int, int, ImageObserver)
3) drawString(String, int, int)
4) add(Component);
5) setVisible(boolean);
6) setLayout(Object);
Answer : 1,2,3
Which of the following layout managers honours the preferred size of a component:
(multiple)
1) CardLayout
2) FlowLayout
3) BorderLayout
4) GridLayout
Answer : 2
Given the following code what is the effect of a being 5:
public class Test {
public void add(int a) {
loop: for (int i = 1; i < 3; i++){
for (int j = 1; j < 3; j++) {
if (a == 5) {
break loop;
}
System.out.println(i * j);
}
}
}
}
1) Generate a runtime error
2) Throw an ArrayIndexOutOfBoundsException
3) Print the values: 1, 2, 2, 4
4) Produces no output
Answer : 4
What is the effect of issuing a wait() method on an object
1) If a notify() method has already been sent to that object then it has no effect
2) The object issuing the call to wait() will halt until another object sends a notify() or notifyAll() method
3) An exception will be raised
4) The object issuing the call to wait() will be automatically synchronized with any other objects using the receiving object.
Answer : 2
The layout of a container can be altered using which of the following methods:
(multiple)
1) setLayout(aLayoutManager);
2) addLayout(aLayoutManager);
3) layout(aLayoutManager);
4) setLayoutManager(aLayoutManager);
Answer : 1
Using a FlowLayout manager, which is the correct way to add elements to a container:
1) add(component);
2) add("Center", component);
3) add(x, y, component);
4) set(component);
Answer : 1
Given that a Button can generate an ActionEvent which listener would you expect to have to implement, in a class which would handle this event?
1) FocusListener
2) ComponentListener
3) WindowListener
4) ActionListener
5) ItemListener
Answer : 4
Which of the following, are valid return types, for listener methods:
1) boolean
2) the type of event handled
3) void
4) Component
Answer : 3
Assuming we have a class which implements the ActionListener interface, which method should be used to register this with a Button?
1) addListener(*);
2) addActionListener(*);
3) addButtonListener(*);
4) setListener(*);
Answer : 2
In order to cause the paint(Graphics) method to execute, which of the following is the most appropriate method to call:
1) paint()
2) repaint()
3) paint(Graphics)
4) update(Graphics)
5) None - you should never cause paint(Graphics) to execute
Answer : 2
Which of the following illustrates the correct way to pass a parameter into an applet:
1) <applet code=Test.class age=33 width=100 height=100>
2) <param name=age value=33>
3) <applet code=Test.class name=age value=33 width=100 height=100>
4) <applet Test 33>
Answer : 2
Which of the following correctly illustrate how an InputStreamReader can be created:
(multiple)
1) new InputStreamReader(new FileInputStream("data"));
2) new InputStreamReader(new FileReader("data"));
3) new InputStreamReader(new BufferedReader("data"));
4) new InputStreamReader("data");
5) new InputStreamReader(System.in);
Answer : 1,5
What is the permanent effect on the file system of writing data to a new FileWriter("report"), given the file report already exists?
1) The data is appended to the file
2) The file is replaced with a new file
3) An exception is raised as the file already exists
4) The data is written to random locations within the file
Answer : 2
What is the effect of adding the sixth element to a vector created in the following manner:
new Vector(5, 10);
1) An IndexOutOfBounds exception is raised.
2) The vector grows in size to a capacity of 10 elements
3) The vector grows in size to a capacity of 15 elements
4) Nothing, the vector will have grown when the fifth element was added
Answer : 3
What is the result of executing the following code when the value of x is 2:
switch (x) {
case 1:
System.out.println(1);
case 2:
case 3:
System.out.println(3);
case 4:
System.out.println(4);
}
1) Nothing is printed out
2) The value 3 is printed out
3) The values 3 and 4 are printed out
4) The values 1, 3 and 4 are printed out
Answer : 3
What is the result of compiling and running the Second class?
Consider the following example:
class First {
public First (String s) {
System.out.println(s);
}
}
public class Second extends First {
public static void main(String args []) {
new Second();
}
}
1) Nothing happens
2) A string is printed to the standard out
3) An instance of the class First is generated
4) An instance of the class Second is created
5) An exception is raised at runtime stating that there is no null parameter constructor in class First.
6) The class second will not compile as there is no null parameter constructor in the class First
Answer : 6
What is the result of executing the following fragment of code:
boolean flag = false;
if (flag = true) {
System.out.println("true");
} else {
System.out.println("false");
}
1) true is printed to standard out
2) false is printed to standard out
3) An exception is raised
4) Nothing happens
Answer : 1
Consider the following classes. What is the result of compiling and running this class?
public class Test {
public static void test() {
this.print();
}
public static void print() {
System.out.println("Test");
}
public static void main(String args []) {
test();
}
}
(multiple)
1) The string Test is printed to the standard out.
2) A runtime exception is raised stating that an object has not been created.
3) Nothing is printed to the standard output.
4) An exception is raised stating that the method test cannot be found.
5) An exception is raised stating that the variable this can only be used within an instance.
6) The class fails to compile stating that the variable this is undefined.
Answer : 6
Examine the following class definition:
public class Test {
public static void test() {
print();
}
public static void print() {
System.out.println("Test");
}
public void print() {
System.out.println("Another Test");
}
}
What is the result of compiling this class:
1) A successful compilation.
2) A warning stating that the class has no main method.
3) An error stating that there is a duplicated method.
4) An error stating that the method test() will call one or other of the print() methods.
Answer : 3
What is the result of compiling and executing the following Java class:
public class ThreadTest extends Thread {
public void run() {
System.out.println("In run");
suspend();
resume();
System.out.println("Leaving run");
}
public static void main(String args []) {
(new ThreadTest()).start();
}
}
1) Compilation will fail in the method main.
2) Compilation will fail in the method run.
3) A warning will be generated for method run.
4) The string "In run" will be printed to standard out.
5) Both strings will be printed to standard out.
6) Nothing will happen.
Answer : 4
Given the following sequence of Java statements, Which of the following options are true:
1. StringBuffer sb = new StringBuffer("abc");
2. String s = new String("abc");
3. sb.append("def");
4. s.append("def");
5. sb.insert(1, "zzz");
6. s.concat(sb);
7. s.trim();
(multiple)
1) The compiler would generate an error for line 1.
2) The compiler would generate an error for line 2.
3) The compiler would generate an error for line 3.
4) The compiler would generate an error for line 4.
5) The compiler would generate an error for line 5.
6) The compiler would generate an error for line 6.
7) The compiler would generate an error for line 7.
Answer : 4,6
What is the result of executing the following Java class:
import java.awt.*;
public class FrameTest extends Frame {
public FrameTest() {
add (new Button("First"));
add (new Button("Second"));
add (new Button("Third"));
pack();
setVisible(true);
}
public static void main(String args []) {
new FrameTest();
}
}
1) Nothing happens.
2) Three buttons are displayed across a window.
3) A runtime exception is generated (no layout manager specified).
4) Only the "first" button is displayed.
5) Only the "second" button is displayed.
6) Only the "third" button is displayed.
Answer : 6
Consider the following tags and attributes of tags, which can be used with the <AAPLET> and </APPLET> tags?
1. CODEBASE
2. ALT
3. NAME
4. CLASS
5. JAVAC
6. HORIZONTALSPACE
7. VERTICALSPACE
8. WIDTH
9. PARAM
10. JAR
(multiple)
1) line 1, 2, 3
2) line 2, 5, 6, 7
3) line 3, 4, 5
4) line 8, 9, 10
5) line 8, 9
Answer : 1,5
Which of the following is a legal way to construct a RandomAccessFile:
1) RandomAccessFile("data", "r");
2) RandomAccessFile("r", "data");
3) RandomAccessFile("data", "read");
4) RandomAccessFile("read", "data");
Answer : 1
Carefully examine the following code, When will the string "Hi there" be printed?
public class StaticTest {
static {
System.out.println("Hi there");
}
public void print() {
System.out.println("Hello");
}
public static void main(String args []) {
StaticTest st1 = new StaticTest();
st1.print();
StaticTest st2 = new StaticTest();
st2.print();
}
}
1) Never.
2) Each time a new instance is created.
3) Once when the class is first loaded into the Java virtual machine.
4) Only when the static method is called explicitly.
Answer : 3
What is the result of the following program:
public class Test {
public static void main (String args []) {
boolean a = false;
if (a = true)
System.out.println("Hello");
else
System.out.println("Goodbye");
}
}
1) Program produces no output but terminates correctly.
2) Program does not terminate.
3) Prints out "Hello"
4) Prints out "Goodbye"
Answer : 3
Examine the following code, it includes an inner class, what is the result:
public final class Test4 {
class Inner {
void test() {
if (Test4.this.flag); {
sample();
}
}
}
private boolean flag = true;
public void sample() {
System.out.println("Sample");
}
public Test4() {
(new Inner()).test();
}
public static void main(String args []) {
new Test4();
}
}
1) Prints out "Sample"
2) Program produces no output but terminates correctly.
3) Program does not terminate.
4) The program will not compile
Answer : 1
Carefully examine the following class:
public class Test5 {
public static void main (String args []) {
/* This is the start of a comment
if (true) {
Test5 = new test5();
System.out.println("Done the test");
}
/* This is another comment */
System.out.println ("The end");
}
}
1) Prints out "Done the test" and nothing else.
2) Program produces no output but terminates correctly.
3) Program does not terminate.
4) The program will not compile.
5) The program generates a runtime exception.
6) The program prints out "The end" and nothing else.
7) The program prints out "Done the test" and "The end"
Answer : 6
What is the result of compiling and running the following applet:
import java.applet.Applet;
import java.awt.*;
public class Sample extends Applet {
private String text = "Hello World";
public void init() {
add(new Label(text));
}
public Sample (String string) {
text = string;
}
}
It is accessed form the following HTML page:
<html>
<title>Sample Applet</title>
<body>
<applet code="Sample.class" width=200 height=200></applet>
</body>
</html>
1) Prints "Hello World".
2) Generates a runtime error.
3) Does nothing.
4) Generates a compile time error.
Answer : 2
What is the effect of compiling and (if possible) running this class:
public class Calc {
public static void main (String args []) {
int total = 0;
for (int i = 0, j = 10; total > 30; ++i, --j) {
System.out.println(" i = " + i + " : j = " + j);
total += (i + j);
}
System.out.println("Total " + total);
}
}
1) Produce a runtime error
2) Produce a compile time error
3) Print out "Total 0"
4) Generate the following as output:
i = 0 : j = 10
i = 1 : j = 9
i = 2 : j = 8
Total 30
Answer : 3
Utility Package
1) What is the Vector class?
ANSWER : The Vector class provides the capability to implement a growable array of objects.
2) What is the Set interface?
ANSWER : The Set interface provides methods for accessing the elements of a finite mathematical set.Sets do not allow duplicate elements.
3) What is Dictionary class?
ANSWER : The Dictionary class is the abstarct super class of Hashtable and Properties class.Dictionary provides the abstarct functions used to store and retrieve objects by key-value.This class allows any object to be used as a key or value.
4) What is the Hashtable class?
ANSWER : The Hashtable class implements a hash table data structure. A hash table indexes and stores objects in a dictionary using hash codes as the objects' keys. Hash codes are integer values that identify objects.
5) What is the Properties class?
Answer : The properties class is a subclass of Hashtable that can be read from or written to a stream.It also provides the capability to specify a set of default values to be used if a specified key is not found in the table. We have two methods load() and save().
6) What changes are needed to make the following prg to compile?
import java.util.*;
class Ques{
public static void main (String args[]) {
String s1 = "abc";
String s2 = "def";
Vector v = new Vector();
v.add(s1);
v.add(s2);
String s3 = v.elementAt(0) + v.elementAt(1);
System.out.println(s3);
}
}
ANSWER : Declare Ques as public B) Cast v.elementAt(0) to a String
C) Cast v.elementAt(1) to an Object. D) Import java.lang
ANSWER : B) Cast v.elementAt(0) to a String
8) What is the output of the prg.
import java.util.*;
class Ques{
public static void main (String args[]) {
String s1 = "abc";
String s2 = "def";
Stack stack = new Stack();
stack.push(s1);
stack.push(s2);
try{
String s3 = (String) stack.pop() + (String) stack.pop() ;
System.out.println(s3);
}catch (EmptyStackException ex){}
}
}
ANSWER : abcdef B) defabc C) abcabc D) defdef
ANSWER : B) defabc
9) Which of the following may have duplicate elements?
ANSWER : Collection B) List C) Map D) Set
ANSWER : A and B Neither a Map nor a Set may have duplicate elements.
10) Can null value be added to a List?
ANSWER : Yes.A Null value may be added to any List.
11) What is the output of the following prg.
import java.util.*;
class Ques{
public static void main (String args[]) {
HashSet set = new HashSet();
String s1 = "abc";
String s2 = "def";
String s3 = "";
set.add(s1);
set.add(s2);
set.add(s1);
set.add(s2);
Iterator i = set.iterator();
while(i.hasNext())
{
s3 += (String) i.next();
}
System.out.println(s3);
}
}
A) abcdefabcdef B) defabcdefabc C) fedcbafedcba D) defabc
ANSWER : D) defabc. Sets may not have duplicate elements.
12) Which of the following java.util classes support internationalization?
A) Locale B) ResourceBundle C) Country D) Language
ANSWER : A and B . Country and Language are not java.util classes.
13) What is the ResourceBundle?
The ResourceBundle class also supports internationalization.
ResourceBundle subclasses are used to store locale-specific resources that can be loaded by a program to tailor the program's appearence to the paticular locale in which it is being run. Resource Bundles provide the capability to isolate a program's locale-specific resources in a standard and modular manner.
14) How are Observer Interface and Observable class, in java.util package, used?
ANSWER : Objects that subclass the Observable class maintain a list of Observers. When an Observable object is updated it invokes the update() method of each of its observers to notify the observers that it has changed state. The Observer interface is implemented by objects that observe Observable objects.
15) Which java.util classes and interfaces support event handling?
ANSWER : The EventObject class and the EventListener interface support event processing.
16) Does java provide standard iterator functions for inspecting a collection of objects?
ANSWER : The Enumeration interface in the java.util package provides a framework for stepping once through a collection of objects. We have two methods in that interface.
public interface Enumeration {
boolean hasMoreElements();
Object nextElement();
}
17) The Math.random method is too limited for my needs- How can I generate random numbers more flexibly?
ANSWER : The random method in Math class provide quick, convienient access to random numbers, but more power and flexibility use the Random class in the java.util package.
double doubleval = Math.random();
The Random class provide methods returning float, int, double, and long values.
nextFloat() // type float; 0.0 <= value < 1.0
nextDouble() // type double; 0.0 <= value < 1.0
nextInt() // type int; Integer.MIN_VALUE <= value <= Integer.MAX_VALUE
nextLong() // type long; Long.MIN_VALUE <= value <= Long.MAX_VALUE
nextGaussian() // type double; has Gaussian("normal") distribution with mean 0.0 and standard deviation 1.0)
Eg. Random r = new Random();
float floatval = r.nextFloat();
18) How can we get all public methods of an object dynamically?
ANSWER : By using getMethods(). It return an array of method objects corresponding to the public methods of this class.
getFields() returns an array of Filed objects corresponding to the public Fields(variables) of this class.
getConstructors() returns an array of constructor objects corresponding to the public constructors of this class.
JDBC
1) What are the steps involved in establishing a connection?
ANSWER : This involves two steps: (1) loading the driver and (2) making the connection.
2) How can you load the drivers?
ANSWER : Loading the driver or drivers you want to use is very simple and involves just one line of code. If, for example, you want to use the JDBC-ODBC Bridge driver, the following code will load it:
Eg.
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
Your driver documentation will give you the class name to use. For instance, if the class name is jdbc.DriverXYZ , you would load the driver with the following line of code:
Eg.
Class.forName("jdbc.DriverXYZ");
3) What Class.forName will do while loading drivers?
ANSWER : It is used to create an instance of a driver and register it with the DriverManager.
When you have loaded a driver, it is available for making a connection with a DBMS.
4) How can you make the connection?
ANSWER : In establishing a connection is to have the appropriate driver connect to the DBMS. The following line of code illustrates the general idea:
Eg.
String url = "jdbc:odbc:Fred";
Connection con = DriverManager.getConnection(url, "Fernanda", "J8");
5) How can you create JDBC statements?
ANSWER : A Statement object is what sends your SQL statement to the DBMS. You simply create a Statement object and then execute it, supplying the appropriate execute method with the SQL statement you want to send. For a SELECT statement, the method to use is executeQuery. For statements that create or modify tables, the method to use is executeUpdate.
Eg.
It takes an instance of an active connection to create a Statement object. In the following example, we use our Connection object con to create the Statement object stmt :
Statement stmt = con.createStatement();
6) How can you retrieve data from the ResultSet?
ANSWER : Step 1.
JDBC returns results in a ResultSet object, so we need to declare an instance of the class ResultSet to hold our results. The following code demonstrates declaring the ResultSet object rs.
Eg.
ResultSet rs = stmt.executeQuery("SELECT COF_NAME, PRICE FROM COFFEES");
Step2.
String s = rs.getString("COF_NAME");
The method getString is invoked on the ResultSet object rs , so getString will retrieve (get) the value stored in the column COF_NAME in the current row of rs
7) What are the different types of Statements?
ANSWER : 1.Statement (use createStatement method) 2. Prepared Statement (Use prepareStatement method) and 3. Callable Statement (Use prepareCall)
8) How can you use PreparedStatement?
ANSWER : This special type of statement is derived from the more general class, Statement.If you want to execute a Statement object many times, it will normally reduce execution time to use a PreparedStatement object instead.
The advantage to this is that in most cases, this SQL statement will be sent to the DBMS right away, where it will be compiled. As a result, the PreparedStatement object contains not just an SQL statement, but an SQL statement that has been precompiled. This means that when the PreparedStatement is executed, the DBMS can just run the PreparedStatement 's SQL statement without having to compile it first.
Eg.
PreparedStatement updateSales = con.prepareStatement("UPDATE COFFEES SET SALES = ? WHERE COF_NAME LIKE ?");
9) What setAutoCommit does?
ANSWER : When a connection is created, it is in auto-commit mode. This means that each individual SQL statement is treated as a transaction and will be automatically committed right after it is executed. The way to allow two or more statements to be grouped into a transaction is to disable auto-commit mode
Eg.
con.setAutoCommit(false);
Once auto-commit mode is disabled, no SQL statements will be committed until you call the method commit explicitly.
Eg.
con.setAutoCommit(false);
PreparedStatement updateSales = con.prepareStatement(
"UPDATE COFFEES SET SALES = ? WHERE COF_NAME LIKE ?");
updateSales.setInt(1, 50);
updateSales.setString(2, "Colombian");
updateSales.executeUpdate();
PreparedStatement updateTotal = con.prepareStatement("UPDATE COFFEES SET TOTAL = TOTAL + ? WHERE COF_NAME LIKE ?");
updateTotal.setInt(1, 50);
updateTotal.setString(2, "Colombian");
updateTotal.executeUpdate();
con.commit();
con.setAutoCommit(true);
10) How to call a Strored Procedure from JDBC?
ANSWER : The first step is to create a CallableStatement object. As with Statement an and PreparedStatement objects, this is done with an open Connection
object. A CallableStatement object contains a call to a stored procedure;
Eg.
CallableStatement cs = con.prepareCall("{call SHOW_SUPPLIERS}");
ResultSet rs = cs.executeQuery();
11) How to Retrieve Warnings?
ANSWER : SQLWarning objects are a subclass of SQLException that deal with database access warnings. Warnings do not stop the execution of an application, as exceptions do; they simply alert the user that something did not happen as planned.
A warning can be reported on a Connection object, a Statement object (including PreparedStatement and CallableStatement objects), or a ResultSet object. Each of these classes has a getWarnings method, which you must invoke in order to see the first warning reported on the calling object
Eg.
SQLWarning warning = stmt.getWarnings();
if (warning != null) {
System.out.println("\n---Warning---\n");
while (warning != null) {
System.out.println("Message: " + warning.getMessage());
System.out.println("SQLState: " + warning.getSQLState());
System.out.print("Vendor error code: ");
System.out.println(warning.getErrorCode());
System.out.println("");
warning = warning.getNextWarning();
}
}
12) How can you Move the Cursor in Scrollable Result Sets ?
ANSWER : One of the new features in the JDBC 2.0 API is the ability to move a result set's cursor backward as well as forward. There are also methods that let you move the cursor to a particular row and check the position of the cursor.
Eg.
Statement stmt = con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,
ResultSet.CONCUR_READ_ONLY);
ResultSet srs = stmt.executeQuery("SELECT COF_NAME, PRICE FROM COFFEES");
The first argument is one of three constants added to the ResultSet API to indicate the type of a ResultSet object: TYPE_FORWARD_ONLY, TYPE_SCROLL_INSENSITIVE , and TYPE_SCROLL_SENSITIVE .
The second argument is one of two ResultSet constants for specifying whether a result set is read-only or updatable: CONCUR_READ_ONLY and CONCUR_UPDATABLE . The point to remember here is that if you specify a type, you must also specify whether it is read-only or updatable. Also, you must specify the type first, and because both parameters are of type int , the compiler will not complain if you switch the order.
Specifying the constant TYPE_FORWARD_ONLY creates a nonscrollable result set, that is, one in which the cursor moves only forward. If you do not specify any constants for the type and updatability of a ResultSet object, you will automatically get one that is TYPE_FORWARD_ONLY and CONCUR_READ_ONLY
13) What’s the difference between TYPE_SCROLL_INSENSITIVE , and TYPE_SCROLL_SENSITIVE?
ANSWER : You will get a scrollable ResultSet object if you specify one of these ResultSet constants.The difference between the two has to do with whether a result set reflects changes that are made to it while it is open and whether certain methods can be called to detect these changes. Generally speaking, a result set that is TYPE_SCROLL_INSENSITIVE does not reflect changes made while it is still open and one that is TYPE_SCROLL_SENSITIVE does. All three types of result sets will make changes visible if they are closed and then reopened
Eg.
Statement stmt = con.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_READ_ONLY);
ResultSet srs = stmt.executeQuery("SELECT COF_NAME, PRICE FROM COFFEES");
srs.afterLast();
while (srs.previous()) {
String name = srs.getString("COF_NAME");
float price = srs.getFloat("PRICE");
System.out.println(name + " " + price);
}
14) How to Make Updates to Updatable Result Sets?
ANSWER : Another new feature in the JDBC 2.0 API is the ability to update rows in a result set using methods in the Java programming language rather than having to send an SQL command. But before you can take advantage of this capability, you need to create a ResultSet object that is updatable. In order to do this, you supply the ResultSet constant CONCUR_UPDATABLE to the createStatement method.
Eg.
Connection con = DriverManager.getConnection("jdbc:mySubprotocol:mySubName");
Statement stmt = con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,
ResultSet.CONCUR_UPDATABLE);
ResultSet uprs = stmt.executeQuery("SELECT COF_NAME, PRICE FROM COFFEES");
Networking Concepts
1) The API doesn't list any constructors for InetAddress- How do I create an InetAddress instance?
ANSWER : In case of InetAddress the three methods getLocalHost, getByName, getByAllName can be used to create instances.
E.g.
InetAddress add1;
InetAddress add2;
try{
add1 = InetAddress.getByName("java.sun.com");
add2 = InetAddress.getByName("199.22.22.22");
}catch(UnknownHostException e){}
2) Is it possible to get the Local host IP?
ANSWER : Yes. Use InetAddress's getLocalHost method.
3) What's the Factory Method?
ANSWER : Factory methods are merely a convention whereby static methods in a class return an instance of that class. The InetAddress class has no visible constructors. To create an InetAddress object, you have to use one of the available factory methods. In InetAddress the three methods getLocalHost, getByName, getByAllName can be used to create instances of InetAddress.
4) What’s the difference between TCP and UDP?
ANSWER : These two protocols differ in the way they carry out the action of communicating. A TCP protocol establishes a two way connection between a pair of computers, while the UDP protocol is a one-way message sender. The common analogy is that TCP is like making a phone call and carrying on a two-way communication, while UDP is like mailing a letter.
5) What is the Proxy Server?
ANSWER : A proxy server speaks the client side of a protocol to another server. This is often required when clients have certain restrictions on which servers they can connect to. And when several users are hitting a popular web site, a proxy server can get the contents of the web server's popular pages once, saving expensive internetwork transfers while providing faster access to those pages to the clients.
Also, we can get multiple connections for a single server.
6) What are the seven layers of OSI model?
ANSWER : Application, Presentation, Session, Transport, Network, DataLink, Physical Layer.
What Transport Layer does?
ANSWER : It ensures that the mail gets to its destination. If a packet fails to get its destination, it handles the process of notifying the sender and requesting that another packet be sent.
8) What is DHCP?
ANSWER : Dynamic Host Configuration Protocol, a piece of the TCP/IP protocol suite that handles the automatic assignment of IP addresses to clients.
9) What is SMTP?
ANSWER : Simple Mail Transmission Protocol, the TCP/IP Standard for Internet mails. SMTP exchanges mail between servers; contrast this with POP, which transmits mail between a server and a client.
10) In OSI N/w architecture, the dialogue control and token management are responsibilities of...
Answer : Network b) Session c) Application d) DataLink
ANSWER : b) Session Layer.
11) In OSI N/W Architecture, the routing is performed by ______
Answer : Network b) Session c) Application d) DataLink
ANSWER : Answer : Network Layer.
Networking
What is the difference between URL instance and URLConnection instance?
ANSWER : A URL instance represents the location of a resource, and a URLConnection instance represents a link for accessing or communicating with the resource at the location.
2) How do I make a connection to URL?
ANSWER : You obtain a URL instance and then invoke openConnection on it.
URLConnection is an abstract class, which means you can't directly create instances of it using a constructor. We have to invoke openConnection method on a URL instance, to get the right kind of connection for your URL.
Eg. URL url;
URLConnection connection;
try{ url = new URL("...");
conection = url.openConnection();
}catch (MalFormedURLException e) { }
3) What Is a Socket?
A socket is one end-point of a two-way communication link between two programs running on the network. A socket is bound to a port number so that the TCP layer can identify the application that data is destined to be sent.Socket classes are used to represent the connection between a client program and a server program. The java.net package provides two classes--Socket and ServerSocket--which implement the client side of the connection and the server side of the connection, respectively.
What information is needed to create a TCP Socket?
ANSWER : The Local System’s IP Address and Port Number.
And the Remote System's IPAddress and Port Number.
5) What are the two important TCP Socket classes?
ANSWER : Socket and ServerSocket.
ServerSocket is used for normal two-way socket communication. Socket class allows us to read and write through the sockets.
getInputStream() and getOutputStream() are the two methods available in Socket class.
When MalformedURLException and UnknownHostException throws?
ANSWER : When the specified URL is not connected then the URL throw MalformedURLException and If InetAddress’ methods getByName and getLocalHost are unabletoresolve the host name they throwan UnknownHostException.
Servlets
1) What is the servlet?
ANSWER : Servlets are modules that extend request/response-oriented servers, such as Java-enabled web servers. For example, a servlet might be responsible for taking data in an HTML order-entry form and applying the business logic used to update a company's order database.
Servlets are to servers what applets are to browsers. Unlike applets, however, servlets have no graphical user interface.
2) Whats the advantages using servlets than using CGI?
ANSWER : Servlets provide a way to generate dynamic documents that is both easier to write and faster to run. Servlets also address the problem of doing server-side programming with platform-specific APIs: they are developed with the Java Servlet API, a standard Java extension.
3) What are the uses of Servlets?
ANSWER : A servlet can handle multiple requests concurrently, and can synchronize requests. This allows servlets to support systems such as on-line conferencing.
Servlets can forward requests to other servers and servlets.Thus servlets can be used to balance load among several servers that mirror the same content, and to partition a single logical service over several servers, according to task type or organizational boundaries.
4) Which pakage provides interfaces and classes for writing servlets?
ANSWER : javax
5) Whats the Servlet Interfcae?
ANSWER : The central abstraction in the Servlet API is the Servlet interface. All servlets implement this interface, either directly or, more commonly, by extending a class that implements it such as HttpServlet.
Servlets-->Generic Servlet-->HttpServlet-->MyServlet.
The Servlet interface declares, but does not implement, methods that manage the servlet and its communications with clients. Servlet writers provide some or all of these methods when developing a servlet.
6) When a servlet accepts a call from a client, it receives two objects- What are they?
ANSWER : ServeltRequest: Which encapsulates the communication from the client to the server.
ServletResponse: Whcih encapsulates the communication from the servlet back to the client.
ServletRequest and ServletResponse are interfaces defined by the javax.servlet package.
7) What information that the ServletRequest interface allows the servlet access to?
ANSWER : Information such as the names of the parameters passed in by the client, the protocol (scheme) being used by the client, and the names of the remote host that made the request and the server that received it.
The input stream, ServletInputStream.Servlets use the input stream to get data from clients that use application protocols such as the HTTP POST and PUT methods.
8) What information that the ServletResponse interface gives the servlet methods for replying to the client?
ANSWER : It Allows the servlet to set the content length and MIME type of the reply.
Provides an output stream, ServletOutputStream and a Writer through which the servlet can send the reply data.
9) What is the servlet Lifecycle?
ANSWER : Each servlet has the same life cycle:
A server loads and initializes the servlet (init())
The servlet handles zero or more client requests (service())
The server removes the servlet (destroy())
(some servers do this step only when they shut down)
10) How HTTP Servlet handles client requests?
ANSWER : An HTTP Servlet handles client requests through its service method. The service method supports standard HTTP client requests by dispatching each request to a method designed to handle that request. 1
Encapsulation :
Encapsulation is the mechanism that binds together code and the data it manipulates and keeps both safe from outside interference and misuse.
Inheritance:
Inheritance is the process by which one object acquires the properties of another object.
Polymorphism:
Polymorphism is a feature that allows one interface to be used for a general class of actions. The specific action is determined by the exact nature of actions.
Code Blocks:
Two or more statements which is allowed to be grouped into blocks of code is otherwise called as Code Blocks.This is done by enclosing the statements between opening and closing curly braces.
Floating-point numbers:
Floating-point numbers which is also known as real numbers, are used when evaluating expressions that require fractional precision.
Unicode:
Unicode defines a fully international character set that can represent all of the characters found in all human languages. It is a unification of dozens of character sets, such as Latin, Greek, Arabic and many more.
Booleans:
Java has a simple type called boolean, for logical values. It can have only on of two possible values, true or false.
Casting:
A cast is simply an explicit type conversion. To create a conversion between two incompatible types, you must use a cast.
Arrays:
An array is a group of like-typed variables that are referred to by a common name. Arrays offer a convenient means of grouping related information. Arrays of any type can be created and may have one or more dimension.
Relational Operators:
The relational operators determine the relationship that one operand has to the other. They determine the equality and ordering.
11.Short-Circuit Logical Operators:
The secondary versions of the Boolean AND and OR operators are known as short-
circuit logical operators. It is represented by || and &&..
12. Switch:
The switch statement is Java’s multiway branch statement. It provides an easy way to
dispatch execution to different parts of your code based on the value of an
experession.
13. Jump Statements:
Jump statements are the statements which transfer control to another part of your
program. Java Supports three jump statements: break, continue, and return.
14. Instance Variables:
The data, or variable, defined within a class are called instance variable.
C++ Questions
Note : All the programs are tested under Turbo C++ 3.0, 4.5 and Microsoft VC++ 6.0 compilers.
It is assumed that,
Programs run under Windows environment,
The underlying machine is an x86 based system,
Program is compiled using Turbo C/C++ compiler.
The program output may depend on the information based on this assumptions (for example sizeof(int) == 2 may be assumed).
1) class Sample
{
public:
int *ptr;
Sample(int i)
{
ptr = new int(i);
}
~Sample()
{
delete ptr;
}
void PrintVal()
{
cout << "The value is " << *ptr;
}
};
void SomeFunc(Sample x)
{
cout << "Say i am in someFunc " << endl;
}
int main()
{
Sample s1= 10;
SomeFunc(s1);
s1.PrintVal();
}
Answer:
Say i am in someFunc
Null pointer assignment(Run-time error)
Explanation:
As the object is passed by value to SomeFunc the destructor of the object is called when the control returns from the function. So when PrintVal is called it meets up with ptr that has been freed.The solution is to pass the Sample object by reference to SomeFunc:
void SomeFunc(Sample &x)
{
cout << "Say i am in someFunc " << endl;
}
because when we pass objects by refernece that object is not destroyed. while returning from the function.
2) Which is the parameter that is added to every non-static member function when it is called?
Answer:
‘this’ pointer
3) class base
{
public:
int bval;
base(){ bval=0;}
};
class deri:public base
{
public:
int dval;
deri(){ dval=1;}
};
void SomeFunc(base *arr,int size)
{
for(int i=0; i<size; i++,arr++)
cout<<arr->bval;
cout<<endl;
}
int main()
{
base BaseArr[5];
SomeFunc(BaseArr,5);
deri DeriArr[5];
SomeFunc(DeriArr,5);
}
Answer:
00000
01010
Explanation:
The function SomeFunc expects two arguments.The first one is a pointer to an array of base class objects and the second one is the sizeof the array.The first call of someFunc calls it with an array of bae objects, so it works correctly and prints the bval of all the objects. When Somefunc is called the second time the argument passed is the pointeer to an array of derived class objects and not the array of base class objects. But that is what the function expects to be sent. So the derived class pointer is promoted to base class pointer and the address is sent to the function. SomeFunc() knows nothing about this and just treats the pointer as an array of base class objects. So when arr++ is met, the size of base class object is taken into consideration and is incremented by sizeof(int) bytes for bval (the deri class objects have bval and dval as members and so is of size >= sizeof(int)+sizeof(int) ).
4) class base
{
public:
void baseFun(){ cout<<"from base"<<endl;}
};
class deri:public base
{
public:
void baseFun(){ cout<< "from derived"<<endl;}
};
void SomeFunc(base *baseObj)
{
baseObj->baseFun();
}
int main()
{
base baseObject;
SomeFunc(&baseObject);
deri deriObject;
SomeFunc(&deriObject);
}
Answer:
from base
from base
Explanation:
As we have seen in the previous case, SomeFunc expects a pointer to a base class. Since a pointer to a derived class object is passed, it treats the argument only as a base class pointer and the corresponding base function is called.
5) class base
{
public:
virtual void baseFun(){ cout<<"from base"<<endl;}
};
class deri:public base
{
public:
void baseFun(){ cout<< "from derived"<<endl;}
};
void SomeFunc(base *baseObj)
{
baseObj->baseFun();
}
int main()
{
base baseObject;
SomeFunc(&baseObject);
deri deriObject;
SomeFunc(&deriObject);
}
Answer:
from base
from derived
Explanation:
Remember that baseFunc is a virtual function. That means that it supports run-time polymorphism. So the function corresponding to the derived class object is called.
void main()
{
int a, *pa, &ra;
pa = &a;
ra = a;
cout <<"a="<<a <<"*pa="<<*pa <<"ra"<<ra ;
}
/*
Answer :
Compiler Error: 'ra',reference must be initialized
Explanation :
Pointers are different from references. One of the main
differences is that the pointers can be both initialized and assigned,
whereas references can only be initialized. So this code issues an error.
*/
const int size = 5;
void print(int *ptr)
{
cout<<ptr[0];
}
void print(int ptr[size])
{
cout<<ptr[0];
}
void main()
{
int a[size] = {1,2,3,4,5};
int *b = new int(size);
print(a);
print(b);
}
/*
Answer:
Compiler Error : function 'void print(int *)' already has a body
Explanation:
Arrays cannot be passed to functions, only pointers (for arrays, base addresses)
can be passed. So the arguments int *ptr and int prt[size] have no difference
as function arguments. In other words, both the functoins have the same signature and
so cannot be overloaded.
*/
class some{
public:
~some()
{
cout<<"some's destructor"<<endl;
}
};
void main()
{
some s;
s.~some();
}
/*
Answer:
some's destructor
some's destructor
Explanation:
Destructors can be called explicitly. Here 's.~some()' explicitly calls the
destructor of 's'. When main() returns, destructor of s is called again,
hence the result.
*/
#include <iostream.h>
class fig2d
{
int dim1;
int dim2;
public:
fig2d() { dim1=5; dim2=6;}
virtual void operator<<(ostream & rhs);
};
void fig2d::operator<<(ostream &rhs)
{
rhs <<this->dim1<<" "<<this->dim2<<" ";
}
/*class fig3d : public fig2d
{
int dim3;
public:
fig3d() { dim3=7;}
virtual void operator<<(ostream &rhs);
};
void fig3d::operator<<(ostream &rhs)
{
fig2d::operator <<(rhs);
rhs<<this->dim3;
}
*/
void main()
{
fig2d obj1;
// fig3d obj2;
obj1 << cout;
// obj2 << cout;
}
/*
Answer :
5 6
Explanation:
In this program, the << operator is overloaded with ostream as argument.
This enables the 'cout' to be present at the right-hand-side. Normally, 'cout'
is implemented as global function, but it doesn't mean that 'cout' is not possible
to be overloaded as member function.
Overloading << as virtual member function becomes handy when the class in which
it is overloaded is inherited, and this becomes available to be overrided. This is as opposed
to global friend functions, where friend's are not inherited.
*/
class opOverload{
public:
bool operator==(opOverload temp);
};
bool opOverload::operator==(opOverload temp){
if(*this == temp ){
cout<<"The both are same objects\n";
return true;
}
else{
cout<<"The both are different\n";
return false;
}
}
void main(){
opOverload a1, a2;
a1= =a2;
}
Answer :
Runtime Error: Stack Overflow
Explanation :
Just like normal functions, operator functions can be called recursively. This program just illustrates that point, by calling the operator == function recursively, leading to an infinite loop.
class complex{
double re;
double im;
public:
complex() : re(1),im(0.5) {}
bool operator==(complex &rhs);
operator int(){}
};
bool complex::operator == (complex &rhs){
if((this->re == rhs.re) && (this->im == rhs.im))
return true;
else
return false;
}
int main(){
complex c1;
cout<< c1;
}
Answer : Garbage value
Explanation:
The programmer wishes to print the complex object using output
re-direction operator,which he has not defined for his lass.But the compiler instead of giving an error sees the conversion function
and converts the user defined object to standard object and prints
some garbage value.
class complex{
double re;
double im;
public:
complex() : re(0),im(0) {}
complex(double n) { re=n,im=n;};
complex(int m,int n) { re=m,im=n;}
void print() { cout<<re; cout<<im;}
};
void main(){
complex c3;
double i=5;
c3 = i;
c3.print();
}
Answer:
5,5
Explanation:
Though no operator= function taking complex, double is defined, the double on the rhs is converted into a temporary object using the single argument constructor taking double and assigned to the lvalue.
void main()
{
int a, *pa, &ra;
pa = &a;
ra = a;
cout <<"a="<<a <<"*pa="<<*pa <<"ra"<<ra ;
}
Answer :
Compiler Error: 'ra',reference must be initialized
Explanation :
Pointers are different from references. One of the main
differences is that the pointers can be both initialized and assigned,
whereas references can only be initialized. So this code issues an error.
Try it Yourself
1) Determine the output of the 'C++' Codelet.
class base
{
public :
out()
{
cout<<"base ";
}
};
class deri{
public : out()
{
cout<<"deri ";
}
};
void main()
{ deri dp[3];
base *bp = (base*)dp;
for (int i=0; i<3;i++)
(bp++)->out();
}
2) Justify the use of virtual constructors and destructors in C++.
3) Each C++ object possesses the 4 member fns,(which can be declared by the programmer explicitly or by the implementation if they are not available). What are those 4 functions?
4) What is wrong with this class declaration?
class something
{
char *str;
public:
something(){
st = new char[10]; }
~something()
{
delete str;
}
};
5) Inheritance is also known as -------- relationship. Containership as ________ relationship.
6) When is it necessary to use member-wise initialization list (also known as header initialization list) in C++?
7) Which is the only operator in C++ which can be overloaded but NOT inherited.
8) Is there anything wrong with this C++ class declaration?
class temp
{
int value1;
mutable int value2;
public :
void fun(int val)
const{
((temp*) this)->value1 = 10;
value2 = 10;
}
};
1. What is a modifier?
Answer:
A modifier, also called a modifying function is a member function that changes the value of at least one data member. In other words, an operation that modifies the state of an object. Modifiers are also known as ‘mutators’.
2. What is an accessor?
Answer:
An accessor is a class operation that does not modify the state of an object. The accessor functions need to be declared as const operations
3. Differentiate between a template class and class template.
Answer:
Template class:
A generic definition or a parameterized class not instantiated until the client provides the needed information. It’s jargon for plain templates.
Class template:
A class template specifies how individual classes can be constructed much like the way a class specifies how individual objects can be constructed. It’s jargon for plain classes.
4. When does a name clash occur?
Answer:
A name clash occurs when a name is defined in more than one place. For example., two different class libraries could give two different classes the same name. If you try to use many class libraries at the same time, there is a fair chance that you will be unable to compile or link the program because of name clashes.
5. Define namespace.
Answer:
It is a feature in c++ to minimize name collisions in the global name space. This namespace keyword assigns a distinct name to a library that allows other libraries to use the same identifier names without creating any name collisions. Furthermore, the compiler uses the namespace signature for differentiating the definitions.
6. What is the use of ‘using’ declaration.
Answer:
A using declaration makes it possible to use a name from a namespace without the scope operator.
7. What is an Iterator class?
Answer:
A class that is used to traverse through the objects maintained by a container class. There are five categories of iterators:
. input iterators,
. output iterators,
. forward iterators,
. bidirectional iterators,
. random access.
An iterator is an entity that gives access to the contents of a container object without violating encapsulation constraints. Access to the contents is granted on a one-at-a-time basis in order. The order can be storage order (as in lists and queues) or some arbitrary order (as in array indices) or according to some ordering relation (as in an ordered binary tree). The iterator is a construct, which provides an interface that, when called, yields either the next element in the container, or some value denoting the fact that there are no more elements to examine. Iterators hide the details of access to and update of the elements of a container class.
The simplest and safest iterators are those that permit read-only access to the contents of a container class. The following code fragment shows how an iterator might appear in code:
cont_iter:=new cont_iterator();
x:=cont_iter.next();
while x/=none do
...
s(x);
...
x:=cont_iter.next();
end;
In this example, cont_iter is the name of the iterator. It is created on the first line by instantiation of cont_iterator class, an iterator class defined to iterate over some container class, cont. Succesive elements from the container are carried to x. The loop terminates when x is bound to some empty value. (Here, none)In the middle of the loop, there is s(x) an operation on x, the current element from the container. The next element of the container is obtained at the bottom of the loop.
9. List out some of the OODBMS available.
Answer:
. GEMSTONE/OPAL of Gemstone systems.
. ONTOS of Ontos.
. Objectivity of Objectivity inc.
. Versant of Versant object technology.
. Object store of Object Design.
. ARDENT of ARDENT software.
. POET of POET software.
10. List out some of the object-oriented methodologies.
Answer:
. Object Oriented Development (OOD) (Booch 1991,1994).
. Object Oriented Analysis and Design (OOA/D) (Coad and Yourdon 1991).
. Object Modelling Techniques (OMT) (Rumbaugh 1991).
. Object Oriented Software Engineering (Objectory) (Jacobson 1992).
. Object Oriented Analysis (OOA) (Shlaer and Mellor 1992).
. The Fusion Method (Coleman 1991).
11. What is an incomplete type?
Answer:
Incomplete types refers to pointers in which there is non availability of the implementation of the referenced location or it points to some location whose value is not available for modification.
Example:
int *i=0x400 // i points to address 400
*i=0; //set the value of memory location pointed by i.
Incomplete types are otherwise called uninitialized pointers.
12. What is a dangling pointer?
Answer:
A dangling pointer arises when you use the address of an object after its lifetime is over.
This may occur in situations like returning addresses of the automatic variables from a function or using the address of the memory block after it is freed.
13. Differentiate between the message and method.
Answer:
Message Method
Objects communicate by sending messages Provides response to a message.
to each other.
A message is sent to invoke a method. It is an implementation of an operation.
14. What is an adaptor class or Wrapper class?
Answer:
A class that has no functionality of its own. Its member functions hide the use of a third party software component or an object with the non-compatible interface or a non- object- oriented implementation.
15. What is a Null object?
Answer:
It is an object of some class whose purpose is to indicate that a real object of that class does not exist. One common use for a null object is a return value from a member function that is supposed to return an object with some specified properties but cannot find such an object.
16. What is class invariant?
Answer:
A class invariant is a condition that defines all valid states for an object. It is a logical condition to ensure the correct working of a class. Class invariants must hold when an object is created, and they must be preserved under all operations of the class. In particular all class invariants are both preconditions and post-conditions for all operations or member functions of the class.
17. What do you mean by Stack unwinding?
Answer:
It is a process during exception handling when the destructor is called for all local objects between the place where the exception was thrown and where it is caught.
18. Define precondition and post-condition to a member function.
Answer:
Precondition:
A precondition is a condition that must be true on entry to a member function. A class is used correctly if preconditions are never false. An operation is not responsible for doing anything sensible if its precondition fails to hold.
For example, the interface invariants of stack class say nothing about pushing yet another element on a stack that is already full. We say that isful() is a precondition of the push operation.
Post-condition:
A post-condition is a condition that must be true on exit from a member function if the precondition was valid on entry to that function. A class is implemented correctly if post-conditions are never false.
For example, after pushing an element on the stack, we know that isempty() must necessarily hold. This is a post-condition of the push operation.
19. What are the conditions that have to be met for a condition to be an invariant of the class?
Answer:
. The condition should hold at the end of every constructor.
. The condition should hold at the end of every mutator(non-const) operation.
20. What are proxy objects?
Answer:
Objects that stand for other objects are called proxy objects or surrogates.
Example:
template<class T>
class Array2D
{
public:
class Array1D
{
public:
T& operator[] (int index);
const T& operator[] (int index) const;
...
};
Array1D operator[] (int index);
const Array1D operator[] (int index) const;
...
};
The following then becomes legal:
Array2D<float>data(10,20);
........
cout<<data[3][6]; // fine
Here data[3] yields an Array1D object and the operator [] invocation on that object yields the float in position(3,6) of the original two dimensional array. Clients of the Array2D class need not be aware of the presence of the Array1D class. Objects of this latter class stand for one-dimensional array objects that, conceptually, do not exist for clients of Array2D. Such clients program as if they were using real, live, two-dimensional arrays. Each Array1D object stands for a one-dimensional array that is absent from a conceptual model used by the clients of Array2D. In the above example, Array1D is a proxy class. Its instances stand for one-dimensional arrays that, conceptually, do not exist.
21. Name some pure object oriented languages.
Answer:
. Smalltalk,
. Java,
. Eiffel,
. Sather.
22. Name the operators that cannot be overloaded.
Answer:
sizeof . .* .-> :: ?:
23. What is a node class?
Answer:
A node class is a class that,
. relies on the base class for services and implementation,
. provides a wider interface to te users than its base class,
. relies primarily on virtual functions in its public interface
. depends on all its direct and indirect base class
. can be understood only in the context of the base class
. can be used as base for further derivation
. can be used to create objects.
A node class is a class that has added new services or functionality beyond the services inherited from its base class.
24. What is an orthogonal base class?
Answer:
If two base classes have no overlapping methods or data they are said to be independent of, or orthogonal to each other. Orthogonal in the sense means that two classes operate in different dimensions and do not interfere with each other in any way. The same derived class may inherit such classes with no difficulty.
25. What is a container class? What are the types of container classes?
Answer:
A container class is a class that is used to hold objects in memory or external storage. A container class acts as a generic holder. A container class has a predefined behavior and a well-known interface. A container class is a supporting class whose purpose is to hide the topology used for maintaining the list of objects in memory. When a container class contains a group of mixed objects, the container is called a heterogeneous container; when the container is holding a group of objects that are all the same, the container is called a homogeneous container.
26. What is a protocol class?
Answer:
An abstract class is a protocol class if:
. it neither contains nor inherits from classes that contain member data, non-virtual functions, or private (or protected) members of any kind.
. it has a non-inline virtual destructor defined with an empty implementation,
. all member functions other than the destructor including inherited functions, are declared pure virtual functions and left undefined.
27. What is a mixin class?
Answer:
A class that provides some but not all of the implementation for a virtual base class is often called mixin. Derivation done just for the purpose of redefining the virtual functions in the base classes is often called mixin inheritance. Mixin classes typically don't share common bases.
28. What is a concrete class?
Answer:
A concrete class is used to define a useful object that can be instantiated as an automatic variable on the program stack. The implementation of a concrete class is defined. The concrete class is not intended to be a base class and no attempt to minimize dependency on other classes in the implementation or behavior of the class.
29.What is the handle class?
Answer:
A handle is a class that maintains a pointer to an object that is programmatically accessible through the public interface of the handle class.
Explanation:
In case of abstract classes, unless one manipulates the objects of these classes through pointers and references, the benefits of the virtual functions are lost. User code may become dependent on details of implementation classes because an abstract type cannot be allocated statistically or on the stack without its size being known. Using pointers or references implies that the burden of memory management falls on the user. Another limitation of abstract class object is of fixed size. Classes however are used to represent concepts that require varying amounts of storage to implement them.
A popular technique for dealing with these issues is to separate what is used as a single object in two parts: a handle providing the user interface and a representation holding all or most of the object's state. The connection between the handle and the representation is typically a pointer in the handle. Often, handles have a bit more data than the simple representation pointer, but not much more. Hence the layout of the handle is typically stable, even when the representation changes and also that handles are small enough to move around relatively freely so that the user needn’t use the pointers and the references.
30. What is an action class?
Answer:
The simplest and most obvious way to specify an action in C++ is to write a function. However, if the action has to be delayed, has to be transmitted 'elsewhere' before being performed, requires its own data, has to be combined with other actions, etc then it often becomes attractive to provide the action in the form of a class that can execute the desired action and provide other services as well. Manipulators used with iostreams is an obvious example.
Explanation:
A common form of action class is a simple class containing just one virtual function.
class Action
{
public:
virtual int do_it( int )=0;
virtual ~Action( );
}
Given this, we can write code say a member that can store actions for later execution without using pointers to functions, without knowing anything about the objects involved, and without even knowing the name of the operation it invokes. For example:
class write_file : public Action
{
File& f;
public:
int do_it(int)
{
return fwrite( ).suceed( );
}
};
class error_message: public Action
{
response_box db(message.cstr( ),"Continue","Cancel","Retry");
switch (db.getresponse( ))
{
case 0: return 0;
case 1: abort();
case 2: current_operation.redo( );return 1;
}
};
A user of the Action class will be completely isolated from any knowledge of derived classes such as write_file and error_message.
31. When can you tell that a memory leak will occur?
Answer:
A memory leak occurs when a program loses the ability to free a block of dynamically allocated memory.
32.What is a parameterized type?
Answer:
A template is a parameterized construct or type containing generic code that can use or manipulate any type. It is called parameterized because an actual type is a parameter of the code body. Polymorphism may be achieved through parameterized types. This type of polymorphism is called parameteric polymorphism. Parameteric polymorphism is the mechanism by which the same code is used on different types passed as parameters.
33. Differentiate between a deep copy and a shallow copy?
Answer:
Deep copy involves using the contents of one object to create another instance of the same class. In a deep copy, the two objects may contain ht same information but the target object will have its own buffers and resources. the destruction of either object will not affect the remaining object. The overloaded assignment operator would create a deep copy of objects.
Shallow copy involves copying the contents of one object into another instance of the same class thus creating a mirror image. Owing to straight copying of references and pointers, the two objects will share the same externally contained contents of the other object to be unpredictable.
Explanation:
Using a copy constructor we simply copy the data values member by member. This method of copying is called shallow copy. If the object is a simple class, comprised of built in types and no pointers this would be acceptable. This function would use the values and the objects and its behavior would not be altered with a shallow copy, only the addresses of pointers that are members are copied and not the value the address is pointing to. The data values of the object would then be inadvertently altered by the function. When the function goes out of scope, the copy of the object with all its data is popped off the stack.
If the object has any pointers a deep copy needs to be executed. With the deep copy of an object, memory is allocated for the object in free store and the elements pointed to are copied. A deep copy is used for objects that are returned from a function.
34. What is an opaque pointer?
Answer:
A pointer is said to be opaque if the definition of the type to which it points to is not included in the current translation unit. A translation unit is the result of merging an implementation file with all its headers and header files.
35. What is a smart pointer?
Answer:
A smart pointer is an object that acts, looks and feels like a normal pointer but offers more functionality. In C++, smart pointers are implemented as template classes that encapsulate a pointer and override standard pointer operators. They have a number of advantages over regular pointers. They are guaranteed to be initialized as either null pointers or pointers to a heap object. Indirection through a null pointer is checked. No delete is ever necessary. Objects are automatically freed when the last pointer to them has gone away. One significant problem with these smart pointers is that unlike regular pointers, they don't respect inheritance. Smart pointers are unattractive for polymorphic code. Given below is an example for the implementation of smart pointers.
Example:
template <class X>
class smart_pointer
{
public:
smart_pointer(); // makes a null pointer
smart_pointer(const X& x) // makes pointer to copy of x
X& operator *( );
const X& operator*( ) const;
X* operator->() const;
smart_pointer(const smart_pointer <X> &);
const smart_pointer <X> & operator =(const smart_pointer<X>&);
~smart_pointer();
private:
//...
};
This class implement a smart pointer to an object of type X. The object itself is located on the heap. Here is how to use it:
smart_pointer <employee> p= employee("Harris",1333);
Like other overloaded operators, p will behave like a regular pointer,
cout<<*p;
p->raise_salary(0.5);
36. What is reflexive association?
Answer:
The 'is-a' is called a reflexive association because the reflexive association permits classes to bear the is-a association not only with their super-classes but also with themselves. It differs from a 'specializes-from' as 'specializes-from' is usually used to describe the association between a super-class and a sub-class. For example:
Printer is-a printer.
37. What is slicing?
Answer:
Slicing means that the data added by a subclass are discarded when an object of the subclass is passed or returned by value or from a function expecting a base class object.
Explanation:
Consider the following class declaration:
class base
{
...
base& operator =(const base&);
base (const base&);
}
void fun( )
{
base e=m;
e=m;
}
As base copy functions don't know anything about the derived only the base part of the derived is copied. This is commonly referred to as slicing. One reason to pass objects of classes in a hierarchy is to avoid slicing. Other reasons are to preserve polymorphic behavior and to gain efficiency.
38. What is name mangling?
Answer:
Name mangling is the process through which your c++ compilers give each function in your program a unique name. In C++, all programs have at-least a few functions with the same name. Name mangling is a concession to the fact that linker always insists on all function names being unique.
Example:
In general, member names are made unique by concatenating the name of the member with that of the class e.g. given the declaration:
class Bar
{
public:
int ival;
...
};
ival becomes something like:
// a possible member name mangling
ival__3Bar
Consider this derivation:
class Foo : public Bar
{
public:
int ival;
...
}
The internal representation of a Foo object is the concatenation of its base and derived class members.
// Pseudo C++ code
// Internal representation of Foo
class Foo
{
public:
int ival__3Bar;
int ival__3Foo;
...
};
Unambiguous access of either ival members is achieved through name mangling. Member functions, because they can be overloaded, require an extensive mangling to provide each with a unique name. Here the compiler generates the same name for the two overloaded instances(Their argument lists make their instances unique).
39. What are proxy objects?
Answer:
Objects that points to other objects are called proxy objects or surrogates. Its an object that provides the same interface as its server object but does not have any functionality. During a method invocation, it routes data to the true server object and
40. Differentiate between declaration and definition in C++.
Answer:
A declaration introduces a name into the program; a definition provides a unique description of an entity (e.g. type, instance, and function). Declarations can be repeated in a given scope, it introduces a name in a given scope. There must be exactly one definition of every object, function or class used in a C++ program.
A declaration is a definition unless:
. it declares a function without specifying its body,
. it contains an extern specifier and no initializer or function body,
. it is the declaration of a static class data member without a class definition,
it is a class name definition,
it is a typedef declaration.
A definition is a declaration unless:
. it defines a static class data member,
. it defines a non-inline member function.
41. What is cloning?
Answer:
An object can carry out copying in two ways i.e. it can set itself to be a copy of another object, or it can return a copy of itself. The latter process is called cloning.
42. Describe the main characteristics of static functions.
Answer:
The main characteristics of static functions include,
. It is without the a this pointer,
. It can't directly access the non-static members of its class
. It can't be declared const, volatile or virtual.
. It doesn't need to be invoked through an object of its class, although for convenience, it may.
43. Will the inline function be compiled as the inline function always? Justify.
Answer:
An inline function is a request and not a command. Hence it won't be compiled as an inline function always.
Explanation:
Inline-expansion could fail if the inline function contains loops, the address of an inline function is used, or an inline function is called in a complex expression. The rules for inlining are compiler dependent.
44. Define a way other than using the keyword inline to make a function inline.
Answer:
The function must be defined inside the class.
45. How can a '::' operator be used as unary operator?
Answer:
The scope operator can be used to refer to members of the global namespace. Because the global namespace doesn’t have a name, the notation :: member-name refers to a member of the global namespace. This can be useful for referring to members of global namespace whose names have been hidden by names declared in nested local scope. Unless we specify to the compiler in which namespace to search for a declaration, the compiler simple searches the current scope, and any scopes in which the current scope is nested, to find the declaration for the name.
46. What is placement new?
Answer:
When you want to call a constructor directly, you use the placement new. Sometimes you have some raw memory that's already been allocated, and you need to construct an object in the memory you have. Operator new's special version placement new allows you to do it.
class Widget
{
public :
Widget(int widgetsize);
...
Widget* Construct_widget_int_buffer(void *buffer,int widgetsize)
{
return new(buffer) Widget(widgetsize);
}
};
This function returns a pointer to a Widget object that's constructed within the buffer passed to the function. Such a function might be useful for applications using shared memory or memory-mapped I/O, because objects in such applications must be placed at specific addresses or in memory allocated by special routines.
OOAD
1. What do you mean by analysis and design?
Analysis:
Basically, it is the process of determining what needs to be done before how it should be done. In order to accomplish this, the developer refers the existing systems and documents. So, simply it is an art of discovery.
Design:
It is the process of adopting/choosing the one among the many, which best accomplishes the users needs. So, simply, it is compromising mechanism.
2. What are the steps involved in designing?
Before getting into the design the designer should go through the SRS prepared by the System Analyst.
The main tasks of design are Architectural Design and Detailed Design.
In Architectural Design we find what are the main modules in the problem domain.
In Detailed Design we find what should be done within each module.
3. What are the main underlying concepts of object orientation?
Objects, messages, class, inheritance and polymorphism are the main concepts of object orientation.
4. What do u meant by "SBI" of an object?
SBI stands for State, Behavior and Identity. Since every object has the above three.
State:
It is just a value to the attribute of an object at a particular time.
. Behaviour:
It describes the actions and their reactions of that object.
. Identity:
An object has an identity that characterizes its own existence. The identity makes it possible to distinguish any object in an unambiguous way, and independently from its state.
5. Differentiate persistent & non-persistent objects?
Persistent refers to an object's ability to transcend time or space. A persistent object stores/saves its state in a permanent storage system with out losing the information represented by the object.
A non-persistent object is said to be transient or ephemeral. By default objects are considered as non-persistent.
6. What do you meant by active and passive objects?
Active objects are one which instigate an interaction which owns a thread and they are responsible for handling control to other objects. In simple words it can be referred as client.
Passive objects are one, which passively waits for the message to be processed. It waits for another object that requires its services. In simple words it can be referred as server.
Diagram:
client server
(Active) (Passive)
7. What is meant by software development method?
Software development method describes how to model and build software systems in a reliable and reproducible way. To put it simple, methods that are used to represent ones' thinking using graphical notations.
8. What are models and meta models?
Model:
It is a complete description of something (i.e. system).
Meta model:
It describes the model elements, syntax and semantics of the notation that allows their manipulation.
9. What do you meant by static and dynamic modeling?
Static modeling is used to specify structure of the objects that exist in the problem domain. These are expressed using class, object and USECASE diagrams.
But Dynamic modeling refers representing the object interactions during runtime. It is represented by sequence, activity, collaboration and statechart diagrams.
10. How to represent the interaction between the modeling elements?
Model element is just a notation to represent (Graphically) the entities that exist in the problem domain. e.g. for modeling element is class notation, object notation etc.
Relationships are used to represent the interaction between the modeling elements.
The following are the Relationships.
Association: Its' just a semantic connection two classes.
e.g.:
Aggregation: Its' the relationship between two classes which are related in the fashion that master and slave. The master takes full rights than the slave. Since the slave works under the master. It is represented as line with diamond in the master area.
ex:
car contains wheels, etc.
car
. Containment: This relationship is applied when the part contained with in the whole part, dies when the whole part dies.
It is represented as darked diamond at the whole part.
example:
class A{
//some code
};
class B
{
A aa; // an object of class A;
// some code for class B;
};
In the above example we see that an object of class A is instantiated with in the class B. so the object class A dies when the object class B dies.we can represnt it in diagram like this.
. Generalization: This relationship used when we want represents a class, which captures the common states of objects of different classes. It is represented as arrow line pointed at the class, which has captured the common states.
. Dependency: It is the relationship between dependent and independent classes. Any change in the independent class will affect the states of the dependent class.
DIAGRAM:
class A class B
11. Why generalization is very strong?
Even though Generalization satisfies Structural, Interface, Behaviour properties. It is mathematically very strong, as it is Antisymmetric and Transitive.
Antisymmetric: employee is a person, but not all persons are employees. Mathematically all As’ are B, but all Bs’ not A.
Transitive: A=>B, B=>c then A=>c.
A. Salesman.
B. Employee.
C. Person.
Note: All the other relationships satisfy all the properties like Structural properties, Interface properties, Behaviour properties.
12. Differentiate Aggregation and containment?
Aggregation is the relationship between the whole and a part. We can add/subtract some properties in the part (slave) side. It won't affect the whole part.
Best example is Car, which contains the wheels and some extra parts. Even though the parts are not there we can call it as car.
But, in the case of containment the whole part is affected when the part within that got affected. The human body is an apt example for this relationship. When the whole body dies the parts (heart etc) are died.
13. Can link and Association applied interchangeably?
No, You cannot apply the link and Association interchangeably. Since link is used represent the relationship between the two objects.
But Association is used represent the relationship between the two classes.
link :: student:Abhilash course:MCA
Association:: student course
14. what is meant by "method-wars"?
Before 1994 there were different methodologies like Rumbaugh, Booch, Jacobson, Meyer etc who followed their own notations to model the systems. The developers were in a dilemma to choose the method which best accomplishes their needs. This particular span was called as "method-wars"
15. Whether unified method and unified modeling language are same or different?
Unified method is convergence of the Rumbaugh and Booch.
Unified modeling lang. is the fusion of Rumbaugh, Booch and Jacobson as well as Betrand Meyer (whose contribution is "sequence diagram"). Its' the superset of all the methodologies.
16. Who were the three famous amigos and what was their contribution to the object community?
The Three amigos namely,
. James Rumbaugh (OMT): A veteran in analysis who came up with an idea about the objects and their Relationships (in particular Associations).
. Grady Booch: A veteran in design who came up with an idea about partitioning of systems into subsystems.
. Ivar Jacobson (Objectory): The father of USECASES, who described about the user and system interaction.
17. Differentiate the class representation of Booch, Rumbaugh and UML?
If you look at the class representaiton of Rumbaugh and UML, It is some what similar and both are very easy to draw.
Representation: OMT UML.
Diagram:
Booch: In this method classes are represented as "Clouds" which are not very easy to draw as for as the developer's view is concern.
Diagram:
18. What is an USECASE? Why it is needed?
A Use Case is a description of a set of sequence of actions that a system performs that yields an observable result of value to a particular action.
In SSAD process <=> In OOAD USECASE. It is represented elliptically.
Representation:
19. Who is an Actor?
An Actor is someone or something that must interact with the system.In addition to that an Actor initiates the process(that is USECASE).
It is represented as a stickman like this.
Diagram:
20. What is guard condition?
Guard condition is one, which acts as a firewall. The access from a particular object can be made only when the particular condition is met.
For Example,
customer check customer number ATM.
Here the object on the customer accesses the ATM facility only when the guard condition is met.
21. Differentiate the following notations?
I: :obj1 :obj2
II: :obj1 :obj2
In the above representation I, obj1 sends message to obj2. But in the case of II the data is transferred from obj1 to obj2.
22. USECASE is an implementation independent notation. How will the designer give the implementation details of a particular USECASE to the programmer?
This can be accomplished by specifying the relationship called "refinement” which talks about the two different abstraction of the same thing.
Or example,
calculate pay calculate
class1 class2 class3
23. Suppose a class acts an Actor in the problem domain, how to represent it in the static model?
In this scenario you can use “stereotype”. Since stereotype is just a string that gives extra semantic to the particular entity/model element. It is given with in the << >>.
class A
<< Actor>>
attributes
methods.
24. Why does the function arguments are called as "signatures"?
The arguments distinguish functions with the same name (functional polymorphism). The name alone does not necessarily identify a unique function. However, the name and its arguments (signatures) will uniquely identify a function.
In real life we see suppose, in class there are two guys with same name, but they can be easily identified by their signatures. The same concept is applied here.
ex:
class person
{
public:
char getsex();
void setsex(char);
void setsex(int);
};
In the above example we see that there is a function setsex() with same name but with different signature.
1. What is a virtual function?
2. Diff b/w func. overloading and func overriding.
3. What is an abstract class?
4. What are "cin" and "cout" - a function or something else?
5. If class C is derived from class B and class B is derived frm class A, define the order in which constructor and destructor would be called if an object of class C is made and explain why?
6. If class A is an abstract class in above question, define the order in which constructor and destructor would be called if an object of class C is made and explain why?
7.What is pure virtual function?
8. Give exmples of virtual func and pure virtual func in real world.
9. Give example of function overloading in real world.
10. Can two parent classes of a derived class have a member function/variable having same name?
11. What is type convertion?
12. Can int be converted into float, float to int, char to int or int to char?
13. What is multilevel and multiple inheritence?
14. Write the structure of switch statement.
15. Some questions by shuffling various case statements, bringing default to top, removing break.
16. Give output:--
int a=5;
cout<<++a<<a<<a++;
17.What is super( ); ?
18. Difference b/w c and c++ .
19. Why is java so popular?
20. What are bytecodes in java?
21. What is platform independence?
22. Write a Query to count the no. of rows in a table.
23. Write a query to find the second largest no. in a column.
24. Who is the author of C++ ?
HR QUESTIONS
1. Introduce yourself.
2. What do you know about HCL.
3. How many lamp posts are there in noida?
4. If you are given a 3 ltr and a 5 ltr jar, give two ways to measure 4 ltr water.
5. If you are given a 7 mtr rod, divide it into 7 equal parts by cutting it only 3 times.
6. Where is mount everest?
7. Can you shift mount everest from Nepal to Russia?
8. What are your plans for higher studies?
9. What are your preferred location of work?
10. Explain the project undertaken by you till date.
11. Give your idea of a good project.
12. What are your strengths and weekness?
13. If we send you to Japan, what are the problems that u'll be facing?
1) What is name of the operator in passing variable no. of arguments to function (Through some Programs)?
Ans: Ellipsis
2) Programs based on Sizeof like
sizeof("HCL") sizeof('make') etc.
3)int main(void)
{
char *ptr;
printf("%c%s",ptr[-1],ptr=&"malfunction"[4]);
}
ans: function
4)
char *ptr1, *ptr2;
char *ptr3, *ptr4;
ptr1="HCL";
ptr2="CTD"
ptr3="Tech"
ptr4="Limited"
printf("%c%s%s%c",ptr[1],ptr2,ptr3,ptr4[8]);
Ans: C CTD Tech%
5)unsigned short int I;
for i=2;i<5;i++
printf("%u",(2<
a.212 b.81632 c.000 d.none
Ans: a.212
7)
char s[]={'a','b','c','/n','c',' '}
char *p,*str,*str1;
p=&s[3];
str=p;
str1=s;
printf("%d", ++*p + ++*str1-32)
Ans:77
8)
a=10, b=11
a^=b^=a^=b++;
printf("%d%d"a,b)
a.1110 b.119 c.1111 d.None
Ans: c.1111
9) Simple programs based on #define
10) A big program was given with Structure concepts. Itz easy.
11) Another #define sum include typedef so be carefull.
#define ABC XYZ
etc.
Ans a=100
12) Some questions based on arrays and loops came.
but I remember nothing else.
FINISHED
1. Which of the following involves context switch,
(a) system call
(b) priviliged instruction
(c) floating poitnt exception
(d) all the above
(e) none of the above
Ans: (a)
2. In OST, terminal emulation is done in
(a) sessions layer
(b) application layer
(c) presentation layer
(d) transport layer
Ans: (b)
3. For a 25MHz processor , what is the time taken by the instruction which needs 3 clock cycles,
(a)120 nano secs
(b)120 micro secs
(c)75 nano secs
(d)75 micro secs
4. For 1 MB memory, the number of address lines required,
(a)11
(b)16
(c)22
(d) 24
Ans. (b)
5. Semaphore is used for
(a) synchronization
(b) dead-lock avoidence
(c) box
(d) none
Ans. (a)
6. Which holds true for the following statement
class c: public A, public B
a) 2 member in class A, B should not have same name
b) 2 member in class A, C should not have same name
c) both
d) none
Ans. (a)
7. Question related to java
8. OLE is used in
a) inter connection in unix
b) interconnection in WINDOWS
c) interconnection in WINDOWS NT
9. Convert a given HEX number to OCTAL
10. Macros and function are related in what aspect?
(a)recursion
(b)varying no of arguments
(c)hypochecking
(d)type declaration
11.Preproconia.. does not do which one of the following
(a) macro
(b) conditional compliclation
(c) in type checking
(d) including load file
Ans. (c)
12. Piggy backing is a technique for
a) Flow control
b) Sequence
c) Acknowledgement
d) retransmition
Ans. (c)
13. In signed magnitude notation what is the minimum value that can be represented with 8 bits
(a) -128
(b) -255
(c) -127
(d) 0
14. There is an employer table with key fields as employer number data
in every n'th row are needed for a simple following queries will get required results.
(a) select A employee number from employee A , where exists from employee B where A employee no. >= B
employee having (count(*) mod n)=0
(b) select employee number from employe A, employe B where A employe number>=B employ number
group by employee number having(count(*) mod n=0 )
(c) both (a) & (b)
(d) none of the above
15. Type duplicates of a row in a table customer with non uniform key field customer number you can see
a) delete from costomer where customer number exists( select distinct customer number from customer having count )
b) delete customer a where customer number in b rowid
c) delete customer a where custermor number in( select customer number from customer a, customer b )
d) none of the above
Section B
1. Given the following statement
enum day = { jan = 1 ,feb=4, april, may}
What is the value of may?
(a) 4
(b) 5
(c) 6
(d) 11
(e) None of the above
2. Find the output for the following C program
main
{int x,j,k;
j=k=6;x=2;
x=j*k;
printf("%d", x);
3. Find the output for the following C program
fn f(x)
{ if(x<=0)
return;
else f(x-1)+x;
}
4. Find the output for the following C program
i=20,k=0;
for(j=1;j<i;j=1+4*(i/j))
{k+=j<10?4:3;
}
printf("%d", k);
Ans. k=4
5. Find the output for the following C program
int i =10
main()
{int i =20,n;
for(n=0;n<=i;)
{int i=10;
i++;
}
printf("%d", i);
Ans. i=20
6. Find the output for the following C program
int x=5;
y= x&y
7.Find the output for the following C program
Y=10;
if( Y++>9 && Y++!=10 && Y++>10)
{printf("%d", Y);
else
printf("%d", Y);
}
Ans. 13
8. Find the output for the following C program
f=(x>y)?x:y
a) f points to max of x and y
b) f points to min of x and y
c)error
Ans. (a)
9. What is the sizeof(long int)
(a) 4 bytes
(b) 2 bytes
(c) compiler dependent
(d) 8 bytes
10. Which of the function operator cannot be over loaded
(a) <=
(b) ?:
(c) ==
(d) *
11. Find the output for the following C program
main()
{intx=2,y=6,z=6;
x=y==z;
printf(%d",x)
}
Aptitude
1. How many of the integers between 25 and 45 are even ?
(A)21 (B)20 (C)11 (D)10 (E)9
Ans:d)10
2. If taxi fares were Rs 1.00 for the first 1/5 mile and Rs 0.20 for each 1/5 miles thereafter. The taxi fare for
a 3-mile ride was
(A)Rs 1.56 (B)Rs 2.40 (C)RS 3.00 (D)Rs 3.80 (E)Rs 4.20
Answer :d)Rs 3.80
3. A computer routine was developed to generate two numbers (x,y) the first being a random number between 0 and 100 inclusive, and the second being less than or equal to the square root of the first. Each of the followin pair satisfies the routine EXCEPT
(A) (99.10) (B) (85.9) (C) (50.7) (D) (1.1) (E) (1.0)
Answer : A) (99.10)
4. A warehouse had a square floor with area 10,000 sq.meters. A rectangular addition was built along one entire side of the warehouse that increased the floor by one-half as much as the original floor. How many meters did the addition extend beyond the original buildings ?
(A)10 (B)20 (C)50 (D)200 (E)500
Ans: c)50
5. A digital wristwatch was set accurately at 8.30 a.m and then lost 2 seconds every 5 minutes. What time was indicated on the watch at 6.30 p.m of the same day if the watch operated continuously that time ?
(A)5:56 B)5:58 (C)6.00 (D)6.23 (E)6.26
Ans :E) 6.26
6. A 5 litre jug contains 4 litres of a salt water solution that is 15 percent salt. If 1.5 litres of the solution spills out of the jug, and the jug is then filled to capacity with water, approximately what percent of the resulting solution in the jug is salt?
(A)7.5% (B)9.5% (C) 10.5% (D)12% (E)15%
Ans :A)7.5%
7. A plane travelled K miles in the first 96 miles of flight time. If it completed the remaining 300 miles of the trip in 1 minute, what was its average speed in miles per hour for the entire trip ?
(A)
(B)
(C)
(D)
(E)
Ans :(300+k)/97 * 60
8. A merchant sells an item at a 20 percent discount. but still makes a gross profit of 20 percent of the cost.What percent of cost would be gross profit on the item have been if it had been sold without the discount?
(A)20% (B)40% (C)50% (D)60% (E)66.6%
Ansr :c) 50%
9. A millionaire bought a job lot of hats 1/4 of which were brown. The millionaire sold 2/3 of the hats including 4/5 of the brown hats. What fraction of the unsold hats were brown.
(A)1/60 (B)1/15 (C)3/20 (D)3/5 (E)3/4
Ans :c)3/20
10. How many integers n greater than and less than 100 are there such that,if the digits of n are reversed, the resulting integer is n+9 ?
(A)5 (B)6 (C)7 (D)8 (E)9
Ans :D)8
11. An investor purchased a shares of stock at a certain price.If the stock increased in price Rs 0.25 per share and the total increase for the x shares was Rs 12.50, how many shares of stock had been purchased ?
(A)25 (B)50 (C)75 (D)100 (E)125
Ans :B)50
12. At a special sale, 5 tickets can be purchased for the price of 3 tickets. If 5 tickets are purchased at the sale, the amount saved will be What percent of the original price of the 5 tickets?
(A) 20% (B) 33.3% (C) 40% (D) 60% (E) 66.6%
Ans :c)40%
13. Working independently, Tina can do a certain job in 12 hours. Working independently, Ann can do the same job in 9 hours. If Tina Works independently at the job for 8 hours and then Ann works independently, how many hours will it take Ann to complete the remainder of the jobs?
(A) 2/3 (B) 3/4 (C) 1 (D) 2 (E) 3
Ans :E)3
14. A decorator bought a bolt of d m number of red chips in any one stack ?
(A) 7 (B) 6 (C) 5 (D) 4 (E) 3
Ans :C) 5
15. A sink has 12 lits of water some quantity of water is taken out. if the remainng water is 6 litres less then the
water taken out then quantity of water taken out is.
a. 3
b. 6
c. 9
d. 1
16. which is the 4 digit number whose second digit is thrice the first digit and 3'rd digit is sum of 1'st and 2'nd and last digit is twice the second digit.
1.2674
2.1349.
3.3343
4.3678
17. In a straight highway 2 cars starts from the same point in opposite directions each travels for 8 Kms and takeleft turn then travel for 6 Kms what is the distance between them now.
1.16
2.20
3.25
4.10
Technical Section
1. In ANSI C which is such thing is not in Java.
typedef struct node
{
int
NODEPTR * NODE
}
2. Q. In signed magnitude notation what is the minimum value that can be represented with 8 bits
a) -128 b) -255 c) -127 d) 0
3. Q. there is an employer table with key feilds as employer no. data in every n'th row are needed for a simple followingqueries will get required results.
a) select A employe no. from employe A , where exists from employe B where A employe no. = B employehaving (count(*) mod n)=0
b) select employe no. from employe A, employe B where A employe no. = B employ no.grouply employe no. having (count(*) mod n=0 )
c) both a& b
d) none of the above
4. Piggybacking is done for, Ans=>Acknowledgement.
5. WHICH IS NOT BASIC data type ans.Char*
6. which of the following statement is valid for string copy
char *srt,*ptr;
a) while(*str) {
*str=*ptr;
++str=++ptr;
}
b ) while(*str)
{*++str=*++ptr};
c)
7. Two variable cannt have the same name in
a)function b) block c) file d)--- C Section
8. #define inc(x) x++
main()
{
int t=1;
printf("%d",inc(t++));
}
9. one or two que for the complicated declaration.
10. Const char *a="Abcd"; char const *a="lmno"; base do this,Two que were there.
11. char *p ;
char q[20];
12. int i,*p=&i;
p=malloc(10);
free(p);
printf("%d",p);
ans : garbage
13. int i=20,*j=&i
f(i)
printf("%d",i);
14. #define val 1+2
printf("%d%d",val/val,val^3)
ans : 3 9
15. #define "this" "#"
#define (x,y) x##y
printf("this","this is")
ans: compilation error (tested)
16. 2^2)+(a^a)
17. int a ,b=7
a=b<4?b<<1:b>4?7>>1:a
ans.3
18. one que on c++ class member function
ans.d
19. work of memory management unit.
20. who relate virtual memory to physical memory ans.os
21. memory is allocated to variable
a)when declared b)when define c)...
22. Question on double linked list
23. Define success 1
define failure -1
if(condition)
printf(success);
else
printf(failure);
ans success
24. main()
{
int var=25,varp;
varp=&var;
varp=10;
fun(varp);
printf(%d%d",var,varp);
ans a)45,45 b)55,55 c) 20,55;
25. u r given two statements
a=(10.15);
b=10,15;
if they are executed what is the output printf("%d%d",a,b);
a)10,15 b)15,10 c)10,10 d)15,15 ans a
26. #define inc(x) x++
main()
{
int t=1;
printf("%d",inc(t++));
}
ans.error
27. main
{int x=1,y=2,z=3;
x=y==z;
printf(x);
}
TCS QUE
TCS PAPER - 01 JUN 2006 - KOLKATTA
Hi Chetanaites
I am Abhijit Chakraborty, recently I have been campus recruited from GNIT kolkata by TCS.I am a third year student from electrical background and as you know it's a tough competition for us to enter the software profession..I have found that there is no material for electrical department so I am compiling and sending my preparation to you all.
The test was online and written both.
I am sending you the questions.
Paper consisted of three sections.They are as .
Verbal-30Q-20mins
Logical/Quantitative-38Q-40mins
Critical-12Q-30mins
So the total exam is for 50mins and not 60 mins as it had been told by most of the passouts who got through..For online test there is a specific time cut-out based on the qubex software they have used but for the written there is no time scheduling you can start anywhere you like..
Cut off for written was 50 and for online it was 42 and not 38 as told by the others..
Now the questions that came.
Verbal: Synonyms:
Brim
Renounce
Caprice
Brash
Limber
Admonish
Tranquil
Moribund
Mundane
Antonyms (This came mostly from GRE Barron's Antonyms exercise)
Encumber
Opacity
Bilk
Luminary
Spur
Stupefy
Pulchritude
Slack
Occlude
Ambiguity
Logical/Quatitative:
Complete the series 2, 7, 24, 77, ----? Ans: 238
find value ##+25-++# 16 , where # denotes double and + denotes square root
Ans: 621
in a two dimensional array X(9,7) which each element occupying 4 bytes of memory with address of the first element X(1,1) is 3000, find the address of X(8,5).
Ans: 3212
In the word ORGANISATIONAL if the first and second, third and fourth, fourth and fifth, fifth and sixth words are interchanged up to the last letter, what would be the tenth letter from right????
Ans:I
What is the largest Prime Number that can be stored in 8-bit memory?
Ans:251
Select odd one out Java, LISP, SMALLTALK, EIFFEL Ans: effiel
Select odd one out sql, DB2, SYBASE, HTTP Ans:HTTP
The size of program is n. and the memory occupied by the program is given by M= square root of 4000n.if the size of the program is increased by 1% then how much memory now occupied? Ans:0.5%(SQRT 101N)
A and B do a work in 7 days. If A does double as B the how many days take A to do? Ans: 10.5
Find the value of the 678 to the base 7. Ans: 1656
Which of the following highest Standard deviation
7, - 7, 7,-7, 7,-7 b) 7, 7, 7,7,7,7 c) -7, - 7, -7,-7,-7,-7 d) -7, 7, -7, 7,-7, 7 Ans: d)
Which of the following is power of 3 a) 2345 b) 9875 c) 6504 d) 9833
Ans: c)
Which of the following is integer? a) 451/45 b) 8765676/17 c) 34567/76 d) 567845/19 Ans: b)
find the result of the following expression if , M denotes modules operation, R denotes round-off, T denotes truncations M(373,5)+R(3.4) +T(7,7)+R(5,8)
Ans: 19
If TAFJHH is coded as RBEKGI then RBDJK can be coded as?
Ans: qcckj
16.g(0)= -1, G(1)=1 ,G(N) = G(N-1)-G(N-2) , g(6)=? Ans: -2
A power unit is there by the bank of the river of 900 mtr width. a cable is made from power unit to power a plant opposite to that of the river and 3000 mtr away from the power unit. The cost of the cable bellows water Rs5 / mtr and cost of cable on the bank is Rs 4/ mtr. Find the total of laying the cable.
Ans: 12900
In madras, temperature at noon varies according to -t^2/2 + 8t + 3, where t is elapsed time. Find how much tem more or less in 4 pm to 9 pm.
Ans: At 9pm 7.5 more chetana-jobs
The size of the bucket is N kb. The bucket fills at the rate of 0.1 kb per millisecond. A programmer sends a program to receiver. There it waits for 10 milliseconds / and response will be back to programmer in 20 millisecond. How many much time the program takes to get a response back to programmer, after it is sent?
Ans: 30 millisecond
Which of the following do not form triangle? a)5,5,5 b) 3,4,7, c) 3,5,9 d) 81,8,5
Ans: c) options are not right
Which of the following are orthogonal pairs a) 3i+2j b) i+j c) 2i-3j d) 7i+j
Ans: a) + c)
If A, B, C are the mechanisms used separately to reduce the wastage of fuel by 30%, 20%, 10%. What will be the fuel economy if they were used combine?
Ans: 49.6
What is the max possible 3 digit prime number?
Ans: 997
If the vertex (5,7) is placed in the memory. First vertex (1,1) s address is 1245 and then address of (5,7) is ----------
Ans: 1279
A can copy 50 papers in 10 hours while both A & B can copy 70 papers in 10 hours. Then for how many hours required for B to copy 26 papers?
Ans: 13 hours
My flight takes of at 2am from a place at 18N 10E and landed 10 Hrs later at a place with coordinates 36N70W. What is the local time when my plane landed?
Ans: 6.40 am
The number 384 in decimal system is given by (1234) x in the X System of numbers find the value of X a} 5 b) 6 c) 7 d) 8 e) 9
Ans: a)
A man, a woman, and a child can do a piece of work in 6 days. Man only can do it in 24 days. Woman can do it in 16 days and in how many days child can do the same work? Ans: 16
Complete the series. 3, 8, --, 24, --, 48, 63. Ans: 15,35
WHICH SHAPE WILL BE OBTAINED BY USING THESE VALUES OF X ,Y
X Y
0 0.00001
10 1.02
100 1.72
1000 3.00
9999 4.72
Ans: Y= log10(X)
33. VENN DIAGROM below HOW MANY PERSON KNOW ENGLISH MORE THAN FRENCH. HOW MUCH % OF PEOPLE KNOWS ALL THE 3 LANGUAGES. HOW MUCH % OF PEOPLE THOSE WHO KNOWS FRENCH AND GERMAN AND NOT ENGLISH
34. Number of faces, vertices and edges of a cube Ans: 6,8 , 12
http://www.ChetanaS.com
35. A, B and C are 8 bit no's. They are as follows:
A -> 1 1 0 1 1 0 1 1
B -> 0 1 1 1 1 0 1 0
C -> 0 1 1 0 1 1 0 1 (n=intersection, u=union)
Find ((A n B) u C) =? Ans: 29…. A-B is {A} - {A n B}
36. A finishes the work in 10 days & B in 8 days individually. If A works for only 6 days then how many days should B work to complete A's work? Ans: 3.2 days
And few questions from venn diagram..
Critical:
1> Puzzle of a motorist going for the shortest route from city A to city C..
2> Puzzle of the two marriage group in a community,i.e Red and Green..
3> Puzzle that all K's are J's..
All the three are repeated from the model testpaper 1 from GRE Barron's 12th edition.
Regarding the aptitude please go through the GRE barron's antonym exercise and model test papers.This will also do for critical reasoning. Other that this for logical or quatitative go through the past papers you will get through..
Interview:
There was only one person in my panel.But he was more that enough..
Person:Intoduce yourself?
Me:bla bla..
Person:So you r from electrical,and subjest of interest is digital?
Me yes
Person:But how about machine?
Me: I know the basics.
Person:Draw the torque slip grap for single and 3 phase induction motor?
Me: Drawn and explained
Person:Convert the number 32 to octal and hexadecimal?
Me:Done with no problem.
Person:Do you know corona in power system?
Me:Yes,sir and I explained it to him.
Person:How to reduce them?
Me:I explained the various method of reducing corona.
Person:Why do we use octal number system?
Me:To get the tedious long binary data into small memory of the digital circuits.
Person:How in microprossecor 8085 the instructions are executed?
Me:Explained the whole working of 8085 microprocessor
Person:What is stack in data structure and its repective operation?
Me:Explained it and its push pop algorithms explined properly
Person:What do you know in 'C'?
Me:Just the Basics chetanasinterview.com
Person:Write a programe using structure to draw the result for a class?
Me:Written it with no trouble..
http://www.chetanasinterview.com
At this he was very much impressed and asked me if I am feeling comfortable as I was smiling at his every word. I said I am all right. He bid me best of luck and recommended me to HR.
HR Interview:
As I have given 'HANDWRITING ANALYSIS' as my hobby so the two HR person kept on writing pages after pages and gave me to analyse,as I was strong in this groun so I hit the bulls eye and I was selected..To get success through HR write a peculiar hobby and grow interest for it and you are sure to clear it with no doubts..e.g- stock market,finding information about super computers..
APPS
Aptitude Questions
1.One of the following is my secret word:AIM DUE MOD OAT TIE.With the list in front of you, if I were to tell you any one of my secret word, then you would be able to tell me the number of vowels in my secret word.Which is my secret word?
Ans.TIE
2.In the following figure:A B C
D
E F G
H
I
Each of the digits 1, 2, 3, 4, 5, 6, 7, 8, and 9 is:
a)Represented by a different letter in the figure above.
b)Positioned in the figure above so that each of A + B + C,C + D +E,E + F + G, and G + H + I is equal to 13.
Which digit does E represent?
Ans.E is 4
3.One of Mr. Horton,his wife,their son,and Mr. Horton's mother is a doctor and another is a lawyer.
a)If the doctor is younger than the lawyer, then the doctor and the lawyer are not blood relatives.
b)If the doctor is a woman, then the doctor and the lawyer are blood relatives.
c)If the lawyer is a man, then the doctor is a man.
Whose occupation you know?
Ans.Mr. Horton:he is the doctor.
4.Here is a picture of two cubes:
a)The two cubes are exactly alike.
b)The hidden faces indicated by the dots have the same alphabet on them.
Which alphabet-q, r, w, or k is on the faces indicated by the dots?
Ans.q
5.In the following figure:
A D
B G E
C F
Each of the seven digits from 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9 is:
a)Represented by a different letter in the figure above.
b)Positioned in the figure above so that A*B*C,B*G*E, and D*E*F are equal.
Which digit does G represent?
Ans.G represents the digit 2.
6.Mr. and Mrs. Aye and Mr. and Mrs. Bee competed in a chess tournament.Of the three games played:
a)In only the first game werethe two players married to each other.
b)The men won two games and the women won one game.
c)The Ayes won more games than the Bees.
d)Anyone who lost game did not play the subsequent game.
Who did not lose a game?
Ans.Mrs.Bee did not lose a game.
7.Three piles of chips--pile I consists one chip, pile II consists of chips, and pile III consists of three chips--are to be used in game played by Anita and Brinda.The game requires:
a)That each player in turn take only one chip or all chips from just one pile.
b)That the player who has to take the last chip loses.
c)That Anita now have her turn.
From which pile should Anita draw in order to win?
Ans.Pile II
8.Of Abdul, Binoy, and Chandini:
a)Each member belongs to the Tee family whose members always tell the truth or to the El family whose members always lie.
b)Abdul says ''Either I belong or Binoy belongs to a different family from the other two."
Whose family do you name of?
Ans.Binoy's family--El.
9.In a class composed of x girls and y boys what part of the class is composed of girls
A.y/(x + y)
B.x/xy
C.x/(x + y)
D.y/xy
Ans.C
10.What is the maximum number of half-pint bottles of cream that can be filled with a 4-gallon can of cream(2 pt.=1 qt. and 4 qt.=1 gal)
A.16
B.24
C.30
D.64
Ans.D
11.If the operation,^ is defined by the equation x ^ y = 2x + y,what is the value of a in 2 ^ a = a ^ 3
A.0
B.1
C.-1
D.4
Ans.B
12.A coffee shop blends 2 kinds of coffee,putting in 2 parts of a 33p. a gm. grade to 1 part of a 24p. a gm.If the mixture is changed to 1 part of the 33p. a gm. to 2 parts of the less expensive grade,how much will the shop save in blending 100 gms.
A.Rs.90
B.Rs.1.00
C.Rs.3.00
D.Rs.8.00
Ans.C
13.There are 200 questions on a 3 hr examination.Among these questions are 50 mathematics problems.It is suggested that twice as much time be spent on each maths problem as for each other question.How many minutes should be spent on mathematics problems
A.36
B.72
C.60
D.100
Ans.B
14.In a group of 15,7 have studied Latin, 8 have studied Greek, and 3 have not studied either.How many of these studied both Latin and Greek
A.0
B.3
C.4
D.5
Ans.B
15.If 13 = 13w/(1-w) ,then (2w)2 =
A.1/4
B.1/2
C.1
D.2
Ans.C
16. If a and b are positive integers and (a-b)/3.5 = 4/7, then
(A) b < a
(B) b > a
(C) b = a
(D) b >= a
Ans. A
17. In june a baseball team that played 60 games had won 30% of its game played. After a phenomenal winning streak this team raised its average to 50% .How many games must the team have won in a row to attain this average?
A. 12
B. 20
C. 24
D. 30
Ans. C
18. M men agree to purchase a gift for Rs. D. If three men drop out how much more will each have to contribute towards the purchase of the gift/
A. D/(M-3)
B. MD/3
C. M/(D-3)
D. 3D/(M2-3M)
Ans. D
19. A company contracts to paint 3 houses. Mr.Brown can paint a house in 6 days while Mr.Black would take 8 days and Mr.Blue 12 days. After 8 days Mr.Brown goes on vacation and Mr. Black begins to work for a period of 6 days. How many days will it take Mr.Blue to complete the contract?
A. 7
B. 8
C. 11
D. 12
Ans.C
20. 2 hours after a freight train leaves Delhi a passenger train leaves the same station travelling in the same direction at an average speed of 16 km/hr. After travelling 4 hrs the passenger train overtakes the freight train. The average speed of the freight train was?
A. 30
B. 40
C.58
D. 60
Ans. B
21. If 9x-3y=12 and 3x-5y=7 then 6x-2y = ?
A.-5
B. 4
C. 2
D. 8
Ans. D
22. There are 5 red shoes, 4 green shoes. If one draw randomly a shoe what is the probability of getting a red shoe
Ans 5c1/ 9c1
23. What is the selling price of a car? If the cost of the car is Rs.60 and a profit of 10% over selling price is earned
Ans: Rs 66/-
24. 1/3 of girls , 1/2 of boys go to canteen .What factor and total number of classmates go to canteen.
Ans: Cannot be determined.
25. The price of a product is reduced by 30% . By what percentage should it be increased to make it 100%
Ans: 42.857%
26. There is a square of side 6cm . A circle is inscribed inside the square. Find the ratio of the area of circle to square.
Ans. 11/14
27. There are two candles of equal lengths and of different thickness. The thicker one lasts of six hours. The thinner 2 hours less than the thicker one. Ramesh lights the two candles at the same time. When he went to bed he saw the thicker one is twice the length of the thinner one. How long ago did Ramesh light the two candles .
Ans: 3 hours.
28. If M/N = 6/5,then 3M+2N = ?
29. If p/q = 5/4 , then 2p+q= ?
30. If PQRST is a parallelogram what it the ratio of triangle PQS & parallelogram PQRST .
Ans: 1:2
31. The cost of an item is Rs 12.60. If the profit is 10% over selling price what is the selling price ?
Ans: Rs 13.86/-
32. There are 6 red shoes & 4 green shoes . If two of red shoes are drawn what is the probability of getting red shoes
Ans: 6c2/10c2
33. To 15 lts of water containing 20% alcohol, we add 5 lts of pure water. What is % alcohol.
Ans : 15%
34. A worker is paid Rs.20/- for a full days work. He works 1,1/3,2/3,1/8.3/4 days in a week. What is the total amount paid for that worker ?
Ans : 57.50
35. If the value of x lies between 0 & 1 which of the following is the largest?
(a) x
(b) x2
(c) -x
(d) 1/x
Ans : (d)
36. If the total distance of a journey is 120 km .If one goes by 60 kmph and comes back at 40kmph what is the average speed during the journey?
Ans: 48kmph
37. A school has 30% students from Maharashtra .Out of these 20% are Bombey students. Find the total percentage of Bombay?
Ans: 6%
38. An equilateral triangle of sides 3 inch each is given. How many equilateral triangles of side 1 inch can be formed from it?
Ans: 9
39. If A/B = 3/5,then 15A = ?
Ans : 9B
40. Each side of a rectangle is increased by 100% .By what percentage does the area increase?
Ans : 300%
41. Perimeter of the back wheel = 9 feet, front wheel = 7 feet on a certain distance, the front wheel gets 10 revolutions more than the back wheel .What is the distance?
Ans : 315 feet.
42. Perimeter of front wheel =30, back wheel = 20. If front wheel revolves 240 times. How many revolutions will the back wheel take?
Ans: 360 times
43. 20% of a 6 litre solution and 60% of 4 litre solution are mixed. What percentage of the mixture of solution
Ans: 36%
44City A's population is 68000, decreasing at a rate of 80 people per year. City B having population 42000 is increasing at a rate of 120 people per year. In how many years both the cities will have same population?
Ans: 130 years
45Two cars are 15 kms apart. One is turning at a speed of 50kmph and the other at 40kmph . How much time will it take for the two cars to meet?
Ans: 3/2 hours
46A person wants to buy 3 paise and 5 paise stamps costing exactly one rupee. If he buys which of the following number of stamps he won't able to buy 3 paise stamps.
Ans: 9
47There are 12 boys and 15 girls, How many different dancing groups can be formed with 2 boys and 3 girls.
48Which of the following fractions is less than 1/3
(a) 22/62
(b) 15/46
(c) 2/3
(d) 1
Ans: (b)
49There are two circles, one circle is inscribed and another circle is circumscribed over a square. What is the ratio of area of inner to outer circle?
Ans: 1 : 2
50Three types of tea the a,b,c costs Rs. 95/kg,100/kg and70/kg respectively.
How many kgs of each should be blended to produce 100 kg of mixture worth Rs.90/kg,
given that the quntities of band c are equal
a)70,15,15
b)50,25,25
c)60,20,20
d)40,30,30
Ans. (b)
51. in a class, except 18 all are above 50 years.
15 are below 50 years of age. How many people are there
(a) 30
(b) 33
(c) 36
(d) none of these.
Ans. (d)
52. If a boat is moving in upstream with velocity of 14 km/hr and goes downstream with a velocity of 40 km/hr, then what is the speed of the stream ?
(a) 13 km/hr
(b) 26 km/hr
(c) 34 km/hr
(d) none of these
Ans. A
53. Find the value of ( 0.75 * 0.75 * 0.75 - 0.001 ) / ( 0.75 * 0.75 - 0.075 + 0.01)
(a) 0.845
(b) 1.908
(c) 2.312
(d) 0.001
Ans. A
54. A can have a piece of work done in 8 days, B can work three times faster than the A, C can work five times faster than A. How many days will they take to do the work together ?
(a) 3 days
(b) 8/9 days
(c) 4 days
(d) can't say
Ans. B
55. A car travels a certain distance taking 7 hrs in forward journey, during the return journey increased speed 12km/hr takes the times 5 hrs.What is the distance travelled
(a) 210 kms
(b) 30 kms
(c) 20 kms
(c) none of these
Ans. B
56. Instead of multiplying a number by 7, the number is divided by 7. What is the percentage of error obtained ?
57. Find (7x + 4y ) / (x-2y) if x/2y = 3/2 ?
(a) 6
(b) 8
(c) 7
(d) data insufficient
Ans. C
58. A man buys 12 lts of liquid which contains 20% of the liquid and the rest is water. He then mixes it with 10 lts of another mixture with 30% of liquid.What is the % of water in the new mixture?
59. If a man buys 1 lt of milk for Rs.12 and mixes it with 20% water and sells it for Rs.15, then what is the percentage of gain?
60. Pipe A can fill a tank in 30 mins and Pipe B can fill it in 28 mins.If 3/4th of the tank is filled by Pipe B alone and both are opened, how much time is required by both the pipes to fill the tank completely ?
61. If on an item a company gives 25% discount, they earn 25% profit. If they now give 10% discount then what is the profit percentage.
(a) 40%
(b) 55%
(c) 35%
(d) 30%
Ans. D
62. A certain number of men can finish a piece of work in 10 days. If however there were 10 men less it will take 10 days more for the work to be finished. How many men were there originally?
(a) 110 men
(b) 130 men
(c) 100 men
(d) none of these
Ans. A
63. In simple interest what sum amounts of Rs.1120/- in 4 years and Rs.1200/- in 5 years ?
(a) Rs. 500
(b) Rs. 600
(c) Rs. 800
(d) Rs. 900
Ans. C
64. If a sum of money compound annually amounts of thrice itself in 3 years. In how many years
will it become 9 times itself.
(a) 6
(b) 8
(c) 10
(d) 12
Ans A
65. Two trains move in the same direction at 50 kmph and 32 kmph respectively. A man in the slower train
observes the 15 seconds elapse before the faster train completely passes by him.
What is the length of faster train ?
(a) 100m
(b) 75m
(c) 120m
(d) 50m
Ans B
66. How many mashes are there in 1 squrare meter of wire gauge if each mesh
is 8mm long and 5mm wide ?
(a) 2500
(b) 25000
(c) 250
(d) 250000
Ans B
67. x% of y is y% of ?
(a) x/y
(b) 2y
(c) x
(d) can't be determined
Ans. C
68. The price of sugar increases by 20%, by what % should a housewife reduce the consumption of sugar so that expenditure on sugar can be same as before ?
(a) 15%
(b) 16.66%
(c) 12%
(d) 9%
Ans B
69. A man spends half of his salary on household expenses, 1/4th for rent, 1/5th for travel expenses, the man deposits the rest in a bank. If his monthly deposits in the bank amount 50, what is his monthly salary ?
(a) Rs.500
(b) Rs.1500
(c) Rs.1000
(d) Rs. 900
Ans C
70. The population of a city increases @ 4% p.a. There is an additional annual increase of 4% of the population due to the influx of job seekers, find the % increase in population after 2 years ?
71. The ratio of the number of boys and girls in a school is 3:2 Out of these 10% the boys and 25% of girls are scholarship holders. % of students who are not scholarship holders.?
72. 15 men take 21 days of 8 hrs. each to do a piece of work. How many days of 6 hrs. each would it take for 21 women if 3 women do as much work as 2 men?
(a) 30
(b) 20
(c) 19
(d) 29
Ans. A
73. A cylinder is 6 cms in diameter and 6 cms in height. If spheres of the same size are made from the material obtained, what is the diameter of each sphere?
(a) 5 cms
(b) 2 cms
(c) 3 cms
(d) 4 cms
Ans C
74. A rectangular plank (2)1/2 meters wide can be placed so that it is on either side of the diagonal of a square shown below.(Figure is not available)What is the area of the plank?
Ans :7*(2)1/2
75. The difference b/w the compound interest payble half yearly and the simple interest on a
certain sum lent out at 10% p.a for 1 year is Rs 25. What is the sum?
(a) Rs. 15000
(b) Rs. 12000
(c) Rs. 10000
(d) none of these
Ans C
76. What is the smallest number by which 2880 must be divided in order to make it into a
perfect square ?
(a) 3
(b) 4
(c) 5
(d) 6
Ans. C
77. A father is 30 years older than his son however he will be only thrice as old as the son after 5 years
what is father's present age ?
(a) 40 yrs
(b) 30 yrs
(c) 50 yrs
(d) none of these
Ans. A
78. An article sold at a profit of 20% if both the cost price and selling price would be Rs.20/- the profit would be 10% more. What is the cost price of that article?
29. If an item costs Rs.3 in '99 and Rs.203 in '00.What is the % increase in price?
(a) 200/3 %
(b) 200/6 %
(c) 100%
(d) none of these
Ans. A
80. 5 men or 8 women do equal amount of work in a day. a job requires 3 men and 5 women to finish the job in 10 days how many woman are required to finish the job in 14 days.
a) 10
b) 7
c) 6
d) 12
Ans 7
81. A simple interest amount of rs 5000 for six month is rs 200. what is the anual rate of interest?
a) 10%
b) 6%
c) 8%
d) 9%
Ans 8%
82. In objective test a correct ans score 4 marks and on a wrong ans 2 marks are ---. a student score 480 marks from 150 question. how many ans were correct?
a) 120
b) 130
c) 110
d) 150
Ans130.
83. An artical sold at amount of 50% the net sale price is rs 425 .what is the list price of the artical?
a) 500
b) 488
c) 480
d) 510
Ans 500
84. A man leaves office daily at 7pm A driver with car comes from his home to pick him from office and bring back home
One day he gets free at 5:30 and instead of waiting for driver he starts walking towards home.
In the way he meets the car and returns home on car He reaches home 20 minutes earlier than usual.
In how much time does the man reach home usually??
Ans. 1hr 20min
85. A works thrice as much as B. If A takes 60 days less than B to do a work then find the number of days it would take to complete the work if both work together?
Ans. 22½days
86. How many 1's are there in the binary form of 8*1024 + 3*64 + 3
Ans. 4
87. In a digital circuit which was to implement (A B) + (A)XOR(B), the designer implements (A B) (A)XOR(B)
What is the probability of error in it ?
88. A boy has Rs 2. He wins or loses Re 1 at a time If he wins he gets Re 1 and if he loses the game he loses Re 1.
He can loose only 5 times. He is out of the game if he earns Rs 5.
Find the number of ways in which this is possible?
Ans. 16
89. If there are 1024*1280 pixels on a screen and each pixel can have around 16 million colors
Find the memory required for this?
Ans. 4MB
90. On a particular day A and B decide that they would either speak the truth or will lie.
C asks A whether he is speaking truth or lying?
He answers and B listens to what he said. C then asks B what A has said B says "A says that he is a liar"
What is B speaking ?
(a) Truth
(b) Lie
(c) Truth when A lies
(d) Cannot be determined
Ans. (b)
91. What is the angle between the two hands of a clock when time is 8:30
Ans. 75(approx)
92. A student is ranked 13th from right and 8th from left. How many students are there in totality ?
93. A man walks east and turns right and then from there to his left and then 45degrees to
his right.In which direction did he go
Ans. North west
94. A student gets 70% in one subject, 80% in the other. To get an overall of 75% how much should get in third subject.
95. A man shows his friend a woman sitting in a park and says that she the daughter of my grandmother's only son.
What is the relation between the two
Ans. Daughter
96. How many squares with sides 1/2 inch long are needed to cover a rectangle that is 4 ft long and 6 ft wide
(a) 24
(b) 96
(c) 3456
(d) 13824
(e) 14266
97. If a=2/3b , b=2/3c, and c=2/3d what part of d is b/
(a) 8/27
(b) 4/9
(c) 2/3
(d) 75%
(e) 4/3
Ans. (b)
2598Successive discounts of 20% and 15% are equal to a single discount of
(a) 30%
(b) 32%
(c) 34%
(d) 35%
(e) 36
Ans. (b)
99. The petrol tank of an automobile can hold g liters.If a liters was removed when the tank was full, what part of the full tank was removed?
(a)g-a
(b)g/a
(c) a/g
(d) (g-a)/a
(e) (g-a)/g
Ans. (c)
100. If x/y=4 and y is not '0' what % of x is 2x-y
(a)150%
(b)175%
(c)200%
(d)250%
Ans. (b)
Aptitude Questions
1.If 2x-y=4 then 6x-3y=?
(a)15
(b)12
(c)18
(d)10
Ans. (b)
2.If x=y=2z and xyz=256 then what is the value of x?
(a)12
(b)8
(c)16
(d)6
Ans. (b)
3. (1/10)18 - (1/10)20 = ?
(a) 99/1020
(b) 99/10
(c) 0.9
(d) none of these
Ans. (a)
4.Pipe A can fill in 20 minutes and Pipe B in 30 mins and Pipe C can empty the same in 40 mins.If all of them work together, find the time taken to fill the tank
(a) 17 1/7 mins
(b) 20 mins
(c) 8 mins
(d) none of these
Ans. (a)
5. Thirty men take 20 days to complete a job working 9 hours a day.How many hour a day should 40 men work to complete the job?
(a) 8 hrs
(b) 7 1/2 hrs
(c) 7 hrs
(d) 9 hrs
Ans. (b)
6. Find the smallest number in a GP whose sum is 38 and product 1728
(a) 12
(b) 20
(c) 8
(d) none of these
Ans. (c)
7. A boat travels 20 kms upstream in 6 hrs and 18 kms downstream in 4 hrs.Find the speed of the boat in still water and the speed of the water current?
(a) 1/2 kmph
(b) 7/12 kmph
(c) 5 kmph
(d) none of these
Ans. (b)
8. A goat is tied to one corner of a square plot of side 12m by a rope 7m long.Find the area it can graze?
(a) 38.5 sq.m
(b) 155 sq.m
(c) 144 sq.m
(d) 19.25 sq.m
Ans. (a)
9. Mr. Shah decided to walk down the escalator of a tube station. He found that if he walks down 26 steps, he requires 30 seconds to reach the bottom. However, if he steps down 34 stairs he would only require 18 seconds to get to the bottom. If the time is measured from the moment the top step begins to descend to the time he steps off the last step at the bottom, find out the height of the stair way in steps?
Ans.46 steps.
10. The average age of 10 members of a committee is the same as it was 4 years ago, because an old member has been replaced by a young member. Find how much younger is the new member ?
Ans.40 years.
11. Three containers A, B and C have volumes a, b, and c respectively; and container A is full of water while the other two are empty. If from container A water is poured into container B which becomes 1/3 full, and into container C which becomes 1/2 full, how much water is left in container A?
12. ABCE is an isosceles trapezoid and ACDE is a rectangle. AB = 10 and EC = 20. What is the length of AE?
Ans. AE = 10.
13. In the given figure, PA and PB are tangents to the circle at A and B respectively and the chord BC is parallel to tangent PA. If AC = 6 cm, and length of the tangent AP is 9 cm, then what is the length of the chord BC?
Ans. BC = 4 cm.
15 Three cards are drawn at random from an ordinary pack of cards. Find the probability that they will consist of a king, a queen and an ace.
Ans. 64/2210.
16. A number of cats got together and decided to kill between them 999919 mice. Every cat killed an equal number of mice. Each cat killed more mice than there were cats. How many cats do you think there were ?
Ans. 991.
17. If Log2 x - 5 Log x + 6 = 0, then what would the value / values of x be?
Ans. x = e2 or e3.
18. The square of a two digit number is divided by half the number. After 36 is added to the quotient, this sum is then divided by 2. The digits of the resulting number are the same as those in the original number, but they are in reverse order. The ten's place of the original number is equal to twice the difference between its digits. What is the number?
Ans. 46
19.Can you tender a one rupee note in such a manner that there shall be total 50 coins but none of them would be 2 paise coins.?
Ans. 45 one paisa coins, 2 five paise coins, 2 ten paise coins, and 1 twenty-five paise coins.
20.A monkey starts climbing up a tree 20ft. tall. Each hour, it hops 3ft. and slips back 2ft. How much time would it take the monkey to reach the top?
Ans.18 hours.
21. What is the missing number in this series? 8 2 14 6 11 ? 14 6 18 12
Ans. 9
22. A certain type of mixture is prepared by mixing brand A at Rs.9 a kg. with brand B at Rs.4 a kg. If the mixture is worth Rs.7 a kg., how many kgs. of brand A are needed to make 40kgs. of the mixture?
Ans. Brand A needed is 24kgs.
23. A wizard named Nepo says "I am only three times my son's age. My father is 40 years more than twice my age. Together the three of us are a mere 1240 years old." How old is Nepo?
Ans. 360 years old.
24. One dog tells the other that there are two dogs in front of me. The other one also shouts that he too had two behind him. How many are they?
Ans. Three.
25. A man ate 100 bananas in five days, each day eating 6 more than the previous day. How many bananas did he eat on the first day?
Ans. Eight.
26. If it takes five minutes to boil one egg, how long will it take to boil four eggs?
Ans. Five minutes.
27. The minute hand of a clock overtakes the hour hand at intervals of 64 minutes of correct time. How much a day does the clock gain or lose?
Ans. 32 8/11 minutes.
28. Solve for x and y: 1/x - 1/y = 1/3, 1/x2 + 1/y2 = 5/9.
Ans. x = 3/2 or -3 and y = 3 or -3/2.
29. Daal is now being sold at Rs. 20 a kg. During last month its rate was Rs. 16 per kg. By how much percent should a family reduce its consumption so as to keep the expenditure fixed?
Ans. 20 %.
30. Find the least value of 3x + 4y if x2y3 = 6.
Ans. 10.
31. Can you find out what day of the week was January 12, 1979?
Ans. Friday.
32. A garrison of 3300 men has provisions for 32 days, when given at a rate of 850 grams per head. At the end of 7 days a reinforcement arrives and it was found that now the provisions will last 8 days less, when given at the rate of 825 grams per head. How, many more men can it feed?
Ans. 1700 men.
33. From 5 different green balls, four different blue balls and three different red balls, how many combinations of balls can be chosen taking at least one green and one blue ball?
Ans. 3720.
34. Three pipes, A, B, & C are attached to a tank. A & B can fill it in 20 & 30 minutes respectively while C can empty it in 15 minutes. If A, B & C are kept open successively for 1 minute each, how soon will the tank be filled?
Ans. 167 minutes.
35. A person walking 5/6 of his usual rate is 40 minutes late. What is his usual time? Ans. 3 hours 20 minutes.
36.For a motorist there are three ways going from City A to City C. By way of bridge the distance is 20 miles and toll is $0.75. A tunnel between the two cities is a distance of 10 miles and toll is $1.00 for the vehicle and driver and $0.10 for each passenger. A two-lane highway without toll goes east for 30 miles to city B and then 20 miles in a northwest direction to City C.
1. Which is the shortest route from B to C
(a) Directly on toll free highway to City C
(b) The bridge
(c) The Tunnel
(d) The bridge or the tunnel
(e) The bridge only if traffic is heavy on the toll free highway
Ans. (a)
2. The most economical way of going from City A to City B, in terms of toll and distance is to use the
(a) tunnel
(b) bridge
(c) bridge or tunnel
(d) toll free highway
(e) bridge and highway
Ans. (a)
3. Jim usually drives alone from City C to City A every working day. His firm deducts a percentage of employee pay for lateness. Which factor would most influence his choice of the bridge or the tunnel ?
(a) Whether his wife goes with him
(b) scenic beauty on the route
(c) Traffic conditions on the road, bridge and tunnel
(d) saving $0.25 in tolls
(e) price of gasoline consumed in covering additional 10 miles on the bridge
Ans. (a)
4. In choosing between the use of the bridge and the tunnel the chief factor(s) would be:
I. Traffic and road conditions
II. Number of passengers in the car
III. Location of one's homes in the center or outskirts of one of the cities
IV. Desire to save $0.25
(a) I only
(b) II only
(c) II and III only
(d) III and IV only
(e) I and II only
Ans. (a)
37.The letters A, B, C, D, E, F and G, not necessarily in that order, stand for seven consecutive integers from 1 to 10
D is 3 less than A
B is the middle term
F is as much less than B as C is greater than D
G is greater than F
1. The fifth integer is
(a) A
(b) C
(c) D
(d) E
(e) F
Ans. (a)
2. A is as much greater than F as which integer is less than G
(a) A
(b) B
(c) C
(d) D
(e) E
Ans. (a)
3. If A = 7, the sum of E and G is
(a) 8
(b) 10
(c) 12
(d) 14
(e) 16
Ans. (a)
4. A - F = ?
(a) 1
(b) 2
(c) 3
(d) 4
(e) Cannot be determined
Ans. (a)
5. An integer T is as much greater than C as C is greater than E. T can be written as A + E. What is D?
(a) 2
(b) 3
(c) 4
(d) 5
(e) Cannot be determined
Ans. (a)
6. The greatest possible value of C is how much greater than the smallest possible value of D?
(a) 2
(b) 3
(c) 4
(d) 5
(e) 6
Ans. (a)
38.
1. All G's are H's
2. All G's are J's or K's
3. All J's and K's are G's
4. All L's are K's
5. All N's are M's
6. No M's are G's
1. If no P's are K's, which of the following must be true?
(a) All P's are J's
(b) No P is a G
(c) No P is an H
(d) If any P is an H it is a G
(e) If any P is a G it is a J
Ans. (a)
2. Which of the following can be logically deduced from the conditions stated?
(a) No M's are H's
(b) No M's that are not N's are H's
(c) No H's are M's
(d) Some M's are H's
(e) All M's are H's
Ans. (a)
3. Which of the following is inconsistent with one or more of the conditions?
(a) All H's are G's
(b) All H's that are not G's are M's
(c) Some H's are both M's and G's
(d) No M's are H's
(e) All M's are H's
Ans. (a)
4. The statement "No L's are J's" is
I. Logically deducible from the conditions stated
II. Consistent with but not deducible from the conditions stated
III. Deducible from the stated conditions together with the additional statement "No J's are K's"
(a) I only
(b) II only
(c) III only
(d) II and III only
(e) Neither I, II nor III
Ans. (a)
39.In country X, democratic, conservative and justice parties have fought three civil wars in twenty years. TO restore stability an agreement is reached to rotate the top offices President, Prime Minister and Army Chief among the parties so that each party controls one and only one office at all times. The three top office holders must each have two deputies, one from each of the other parties. Each deputy must choose a staff composed of equally members of his or her chiefs party and member of the third party.
1. When Justice party holds one of the top offices, which of the following cannot be true
(a) Some of the staff members within that office are justice party members
(b) Some of the staff members within that office are democratic party members
(c) Two of the deputies within the other offices are justice party members
(d) Two of the deputies within the other offices are conservative party members
(e) Some of the staff members within the other offices are justice party members.
Ans. (a)
2. When the democratic party holds presidency, the staff of the prime minister's deputies are composed
I. One-fourth of democratic party members
II. One-half of justice party members and one-fourth of conservative party members
III. One-half of conservative party members and one-fourth of justice party members.
(a) I only
(b) I and II only
(c) II or III but not both
(d) I and II or I and III
(e) None of these
Ans. (a)
3. Which of the following is allowable under the rules as stated:
(a) More than half of the staff within a given office belonging to a single party
(b) Half of the staff within a given office belonging to a single party
(c) Any person having a member of the same party as his or her immediate superior
(d) Half the total number of staff members in all three offices belonging to a single party
(e) Half the staff members in a given office belonging to parties different from the party of the top office holder in that office.
Ans. (a)
4. The office of the Army Chief passes from Conservative to Justice party. Which of the following must be fired.
(a) The democratic deputy and all staff members belonging to Justice party
(b) Justice party deputy and all his or hers staff members
(c) Justice party deputy and half of his Conservative staff members in the chief of staff office
(d) The Conservative deputy and all of his or her staff members belonging to Conservative party
(e) No deputies and all staff members belonging to conservative parties.
Ans. (a)
40.In recommendations to the board of trustees a tuition increase of $500 per year, the president of the university said "There were no student demonstrations over the previous increases of $300 last year and $200 the year before". If the president's statement is accurate then which of the following can be validly inferred from the information given:
I. Most students in previous years felt that the increases were justified because of increased operating costs.
II. Student apathy was responsible for the failure of students to protest the previous tuition increases.
III. Students are not likely to demonstrate over new tuition increases.
(a) I only
(b) II only
(c) I or II but not both
(d) I, II and III
(e) None
Ans. (a)
41. The office staff of XYZ corporation presently consists of three bookeepers--A, B, C and 5 secretaries D, E, F, G, H. The management is planning to open a new office in another city using 2 bookeepers and 3 secretaries of the present staff . To do so they plan to seperate certain individuals who don't function well together. The following guidelines were established to set up the new office
I. Bookeepers A and C are constantly finding fault with one another and should not be sent together to the new office as a team
II. C and E function well alone but not as a team , they should be seperated
III. D and G have not been on speaking terms and shouldn't go together
IV Since D and F have been competing for promotion they shouldn't be a team
1.If A is to be moved as one of the bookeepers,which of the following cannot be a possible working unit.
A.ABDEH
B.ABDGH
C.ABEFH
D.ABEGH
Ans.B
2.If C and F are moved to the new office,how many combinations are possible
A.1
B.2
C.3
D.4
Ans.A
3.If C is sent to the new office,which member of the staff cannot go with C
A.B
B.D
C.F
D.G
Ans.B
4.Under the guidelines developed,which of the following must go to the new office
A.B
B.D
C.E
D.G
Ans.A
5.If D goes to the new office,which of the following is/are true
I.C cannot go
II.A cannot go
III.H must also go
A.I only
B.II only
C.I and II only
D.I and III only
Ans.D
42.After months of talent searching for an administrative assistant to the president of the college the field of applicants has been narrowed down to 5--A, B, C, D, E .It was announced that the finalist would be chosen after a series of all-day group personal interviews were held.The examining committee agreed upon the following procedure
I.The interviews will be held once a week
II.3 candidates will appear at any all-day interview session
III.Each candidate will appear at least once
IV.If it becomes necessary to call applicants for additonal interviews, no more 1 such applicant should be asked to appear the next week
V.Because of a detail in the written applications,it was agreed that whenever candidate B appears, A should also be present.
VI.Because of travel difficulties it was agreed that C will appear for only 1 interview.
1.At the first interview the following candidates appear A,B,D.Which of the follwing combinations can be called for the interview to be held next week.
A.BCD
B.CDE
C.ABE
D.ABC
Ans.B
2.Which of the following is a possible sequence of combinations for interviews in 2 successive weeks
A.ABC;BDE
B.ABD;ABE
C.ADE;ABC
D.BDE;ACD
Ans.C
3.If A ,B and D appear for the interview and D is called for additional interview the following week,which 2 candidates may be asked to appear with D?
I. A
II B
III.C
IV.E
A.I and II
B.I and III only
C.II and III only
D.III and IV only
Ans.D
4.Which of the following correctly state(s) the procedure followed by the search committee
I.After the second interview all applicants have appeared at least once
II.The committee sees each applicant a second time
III.If a third session,it is possible for all applicants to appear at least twice
A.I only
B.II only
C.III only
D.Both I and II
Ans.A
43. A certain city is served by subway lines A,B and C and numbers 1 2 and 3
When it snows , morning service on B is delayed
When it rains or snows , service on A, 2 and 3 are delayed both in the morning and afternoon
When temp. falls below 30 degrees farenheit afternoon service is cancelled in either the A line or the 3 line,
but not both.
When the temperature rises over 90 degrees farenheit, the afternoon service is cancelled in either the line C or the
3 line but not both.
When the service on the A line is delayed or cancelled, service on the C line which connects the A line, is delayed.
When service on the 3 line is cancelled, service on the B line which connects the 3 line is delayed.
Q1. On Jan 10th, with the temperature at 15 degree farenheit, it snows all day. On how many lines will service be
affected, including both morning and afternoon.
(A) 2
(B) 3
(C) 4
(D) 5
Ans. D
Q2. On Aug 15th with the temperature at 97 degrees farenheit it begins to rain at 1 PM. What is the minimum number
of lines on which service will be affected?
(A) 2
(B) 3
(C) 4
(D) 5
Ans. C
Q3. On which of the following occasions would service be on the greatest number of lines disrupted.
(A) A snowy afternoon with the temperature at 45 degree farenheit
(B) A snowy morning with the temperature at 45 degree farenheit
(C) A rainy afternoon with the temperature at 45 degree farenheit
(D) A rainy afternoon with the temperature at 95 degree farenheit
Ans. B
44. In a certain society, there are two marriage groups, red and brown. No marriage is permitted within a group. On marriage, males become part of their wives groups; women remain in their own group. Children belong to the same group as their parents. Widowers and divorced males revert to the group of their birth. Marriage to more than one person at the same time and marriage to a direct descendant are forbidden
Q1. A brown female could have had
I. A grandfather born Red
II. A grandmother born Red
III Two grandfathers born Brown
(A) I only
(B) III only
(C) I, II and III
(D) I and II only
Ans. D
Q2. A male born into the brown group may have
(A) An uncle in either group
(B) A brown daughter
(C) A brown son
(D) A son-in-law born into red group
Ans. A
Q3. Which of the following is not permitted under the rules as stated.
(A) A brown male marrying his father's sister
(B) A red female marrying her mother's brother
(C) A widower marrying his wife's sister
(D) A widow marrying her divorced daughter's ex-husband
Ans. B
Q4. If widowers and divorced males retained their group they had upon marrying which of the following would be permissible ( Assume that no previous marriage occurred)
(A) A woman marrying her dead sister's husband
(B) A woman marrying her divorced daughter's ex-husband
(C) A widower marrying his brother's daughter
(D) A woman marrying her mother's brother who is a widower.
Ans. D
Q5. I. All G's are H's
II. All G's are J's or K's
III All J's and K's are G's
IV All L's are K's
V All N's are M's
VI No M's are G's
45. There are six steps that lead from the first to the second floor. No two people can be on the same step
Mr. A is two steps below Mr. C
Mr. B is a step next to Mr. D
Only one step is vacant ( No one standing on that step )
Denote the first step by step 1 and second step by step 2 etc.
1. If Mr. A is on the first step, Which of the following is true?
(a) Mr. B is on the second step
(b) Mr. C is on the fourth step.
(c) A person Mr. E, could be on the third step
(d) Mr. D is on higher step than Mr. C.
Ans: (d)
2. If Mr. E was on the third step & Mr. B was on a higher step than Mr. E which step must be vacant
(a) step 1
(b) step 2
(c) step 4
(d) step 5
(e) step 6
Ans: (a)
3. If Mr. B was on step 1, which step could A be on?
(a) 2&e only
(b) 3&5 only
(c) 3&4 only
(d) 4&5 only
(e) 2&4 only
Ans: (c)
4. If there were two steps between the step that A was standing and the step that B was standing on, and A was on a higher step than D , A must be on step
(a) 2
(b) 3
(c) 4
(d) 5
(e) 6
Ans: (c)
5. Which of the following is false
i. B&D can be both on odd-numbered steps in one configuration
ii. In a particular configuration A and C must either both an odd numbered steps or both an even-numbered steps
iii. A person E can be on a step next to the vacant step.
(a) i only
(b) ii only
(c) iii only
(d) both i and iii
Ans: (c)
46. Six swimmers A, B, C, D, E, F compete in a race. The outcome is as follows.
i. B does not win.
ii. Only two swimmers separate E & D
iii. A is behind D & E
iv. B is ahead of E , with one swimmer intervening
v. F is a head of D
1. Who stood fifth in the race ?
(a) A
(b) B
(c) C
(d) D
(e) E
Ans: (e)
2. How many swimmers seperate A and F ?
(a) 1
(b) 2
(c) 3
(d) 4
(e) cannot be determined
Ans: (d)
3. The swimmer between C & E is
(a) none
(b) F
(c) D
(d) B
(e) A
Ans: (a)
4. If the end of the race, swimmer D is disqualified by the Judges then swimmer B finishes in which place
(a) 1
(b) 2
(c) 3
(d) 4
(e) 5
Ans: (b)
47. Five houses lettered A,B,C,D, & E are built in a row next to each other. The houses are lined up in the order A,B,C,D, & E. Each of the five houses has a colored chimney. The roof and chimney of each housemust be painted as follows.
i. The roof must be painted either green,red ,or yellow.
ii. The chimney must be painted either white, black, or red.
iii. No house may have the same color chimney as the color of roof.
iv. No house may use any of the same colors that the every next house uses.
v. House E has a green roof.
vi. House B has a red roof and a black chimney
1. Which of the following is true ?
(a) At least two houses have black chimney.
(b) At least two houses have red roofs.
(c) At least two houses have white chimneys
(d) At least two houses have green roofs
(e) At least two houses have yellow roofs
Ans: (c)
2. Which must be false ?
(a) House A has a yellow roof
(b) House A & C have different color chimney
(c) House D has a black chimney
(d) House E has a white chimney
(e) House B&D have the same color roof.
Ans: (b)
3. If house C has a yellow roof. Which must be true.
(a) House E has a white chimney
(b) House E has a black chimney
(c) House E has a red chimney
(d) House D has a red chimney
(e) House C has a black chimney
Ans: (a)
4. Which possible combinations of roof & chimney can house
I. A red roof 7 a black chimney
II. A yellow roof & a red chimney
III. A yellow roof & a black chimney
(a) I only
(b) II only
(c) III only
(d) I & II only
(e) I&II&III
Ans: (e)
48. Find x+2y
(i). x+y=10
(ii). 2x+4y=20
Ans: (b)
49. Is angle BAC is a right angle
(i) AB=2BC
(2) BC=1.5AC
Ans: (e)
50. Is x greater than y
(i) x=2k
(ii) k=2y
Ans: (e)
Java Basics
1.The Java interpreter is used for the execution of the source code.
True
False
Ans: a.
2) On successful compilation a file with the class extension is created.
a) True
b) False
Ans: a.
3) The Java source code can be created in a Notepad editor.
a) True
b) False
Ans: a.
4) The Java Program is enclosed in a class definition.
a) True
b) False
Ans: a.
5) What declarations are required for every Java application?
Ans: A class and the main( ) method declarations.
6) What are the two parts in executing a Java program and their purposes?
Ans: Two parts in executing a Java program are:
Java Compiler and Java Interpreter.
The Java Compiler is used for compilation and the Java Interpreter is used for execution of the application.
7) What are the three OOPs principles and define them?
Ans : Encapsulation, Inheritance and Polymorphism are the three OOPs
Principles.
Encapsulation:
Is the Mechanism that binds together code and the data it manipulates, and keeps both safe from outside interference and misuse.
Inheritance:
Is the process by which one object acquires the properties of another object.
Polymorphism:
Is a feature that allows one interface to be used for a general class of actions.
8) What is a compilation unit?
Ans : Java source code file.
9) What output is displayed as the result of executing the following statement?
System.out.println("// Looks like a comment.");
// Looks like a comment
The statement results in a compilation error
Looks like a comment
No output is displayed
Ans : a.
10) In order for a source code file, containing the public class Test, to successfully compile, which of the following must be true?
It must have a package statement
It must be named Test.java
It must import java.lang
It must declare a public class named Test
Ans : b
11) What are identifiers and what is naming convention?
Ans : Identifiers are used for class names, method names and variable names. An identifier may be any descriptive sequence of upper case & lower case letters,numbers or underscore or dollar sign and must not begin with numbers.
12) What is the return type of program’s main( ) method?
Ans : void
13) What is the argument type of program’s main( ) method?
Ans : string array.
14) Which characters are as first characters of an identifier?
Ans : A – Z, a – z, _ ,$
15) What are different comments?
Ans : 1) // -- single line comment
2) /* --
*/ multiple line comment
3) /** --
*/ documentation
16) What is the difference between constructor method and method?
Ans : Constructor will be automatically invoked when an object is created. Whereas method has to be call explicitly.
17) What is the use of bin and lib in JDK?
Ans : Bin contains all tools such as javac, applet viewer, awt tool etc., whereas Lib
contains all packages and variables.
Data types,variables and Arrays
1) What is meant by variable?
Ans: Variables are locations in memory that can hold values. Before assigning any value to a variable, it must be declared.
2) What are the kinds of variables in Java? What are their uses?
Ans: Java has three kinds of variables namely, the instance variable, the local variable and the class variable.
Local variables are used inside blocks as counters or in methods as temporary variables and are used to store information needed by a single method.
Instance variables are used to define attributes or the state of a particular object and are used to store information needed by multiple methods in the objects.
Class variables are global to a class and to all the instances of the class and are useful for communicating between different objects of all the same class or keeping track of global states.
3) How are the variables declared?
Ans: Variables can be declared anywhere in the method definition and can be initialized during their declaration.They are commonly declared before usage at the beginning of the definition.
Variables with the same data type can be declared together. Local variables must be given a value before usage.
4) What are variable types?
Ans: Variable types can be any data type that java supports, which includes the eight primitive data types, the name of a class or interface and an array.
5) How do you assign values to variables?
Ans: Values are assigned to variables using the assignment operator =.
6) What is a literal? How many types of literals are there?
Ans: A literal represents a value of a certain type where the type describes how that value behaves.
There are different types of literals namely number literals, character literals,
boolean literals, string literals,etc.
7) What is an array?
Ans: An array is an object that stores a list of items.
8) How do you declare an array?
Ans: Array variable indicates the type of object that the array holds.
Ex: int arr[];
9) Java supports multidimensional arrays.
a)True
b)False
Ans: a.
10) An array of arrays can be created.
a)True
b)False
Ans: a.
11) What is a string?
Ans: A combination of characters is called as string.
12) Strings are instances of the class String.
a)True
b)False
Ans: a.
13) When a string literal is used in the program, Java automatically creates instances of the string class.
a)True
b)False
Ans: a.
14) Which operator is to create and concatenate string?
Ans: Addition operator(+).
15) Which of the following declare an array of string objects?
String[ ] s;
String [ ]s:
String[ s]:
String s[ ]:
Ans : a, b and d
16) What is the value of a[3] as the result of the following array declaration?
1
2
3
4
Ans : d
17) Which of the following are primitive types?
byte
String
integer
Float
Ans : a.
18) What is the range of the char type?
0 to 216
0 to 215
0 to 216-1
0 to 215-1
Ans. d
19) What are primitive data types?
Ans : byte, short, int, long
float, double
boolean
char
20) What are default values of different primitive types?
Ans : int - 0
short - 0
byte - 0
long - 0 l
float - 0.0 f
double - 0.0 d
boolean - false
char - null
21) Converting of primitive types to objects can be explicitly.
a)True
b)False
Ans: b.
22) How do we change the values of the elements of the array?
Ans : The array subscript expression can be used to change the values of the elements of the array.
23) What is final varaible?
Ans : If a variable is declared as final variable, then you can not change its value. It becomes constant.
24) What is static variable?
Ans : Static variables are shared by all instances of a class.
Operators
1) What are operators and what are the various types of operators available in Java?
Ans: Operators are special symbols used in expressions.
The following are the types of operators:
Arithmetic operators,
Assignment operators,
Increment & Decrement operators,
Logical operators,
Biwise operators,
Comparison/Relational operators and
Conditional operators
2) The ++ operator is used for incrementing and the -- operator is used for
decrementing.
a)True
b)False
Ans: a.
3) Comparison/Logical operators are used for testing and magnitude.
a)True
b)False
Ans: a.
4) Character literals are stored as unicode characters.
a)True
b)False
Ans: a.
5) What are the Logical operators?
Ans: OR(|), AND(&), XOR(^) AND NOT(~).
6) What is the % operator?
Ans : % operator is the modulo operator or reminder operator. It returns the reminder of dividing the first operand by second operand.
7) What is the value of 111 % 13?
3
5
7
9
Ans : c.
8) Is &&= a valid operator?
Ans : No.
9) Can a double value be cast to a byte?
Ans : Yes
10) Can a byte object be cast to a double value ?
Ans : No. An object cannot be cast to a primitive value.
11) What are order of precedence and associativity?
Ans : Order of precedence the order in which operators are evaluated in expressions.
Associativity determines whether an expression is evaluated left-right or right-left.
12) Which Java operator is right associativity?
Ans : = operator.
13) What is the difference between prefix and postfix of -- and ++ operators?
Ans : The prefix form returns the increment or decrement operation and returns the value of the increment or decrement operation.
The postfix form returns the current value of all of the expression and then
performs the increment or decrement operation on that value.
14) What is the result of expression 5.45 + "3,2"?
The double value 8.6
The string ""8.6"
The long value 8.
The String "5.453.2"
Ans : d
15) What are the values of x and y ?
x = 5; y = ++x;
Ans : x = 6; y = 6
16) What are the values of x and z?
x = 5; z = x++;
Ans : x = 6; z = 5
Control Statements
1) What are the programming constructs?
Ans: a) Sequential
b) Selection -- if and switch statements
c) Iteration -- for loop, while loop and do-while loop
2) class conditional {
public static void main(String args[]) {
int i = 20;
int j = 55;
int z = 0;
z = i < j ? i : j; // ternary operator
System.out.println("The value assigned is " + z);
}
}
What is output of the above program?
Ans: The value assigned is 20
3) The switch statement does not require a break.
a)True
b)False
Ans: b.
4) The conditional operator is otherwise known as the ternary operator.
a)True
b)False
Ans: a.
5) The while loop repeats a set of code while the condition is false.
a)True
b)False
Ans: b.
6) The do-while loop repeats a set of code atleast once before the condition is tested.
a)True
b)False
Ans: a.
7) What are difference between break and continue?
Ans: The break keyword halts the execution of the current loop and forces control out of the loop.
The continue is similar to break, except that instead of halting the execution of the loop, it starts the next iteration.
8) The for loop repeats a set of statements a certain number of times until a condition is matched.
a)True
b)False
Ans: a.
9) Can a for statement loop indefintely?
Ans : Yes.
10) What is the difference between while statement and a do statement/
Ans : A while statement checks at the beginning of a loop to see whether the next loop iteration should occur.
A do statement checks at the end of a loop to see whether the next iteration of a loop should occur. The do statement will always execute the body of a loop at least once.
Introduction to Classes and Methods
1) Which is used to get the value of the instance variables?
Ans: Dot notation.
2) The new operator creates a single instance named class and returns a
reference to that object.
a)True
b)False
Ans: a.
3) A class is a template for multiple objects with similar features.
a)True
b)False
Ans: a.
4) What is mean by garbage collection?
Ans: When an object is no longer referred to by any variable, Java automatically
reclaims memory used by that object. This is known as garbage collection.
5) What are methods and how are they defined?
Ans: Methods are functions that operate on instances of classes in which they are defined.Objects can communicate with each other using methods and can call methods in other classes.
Method definition has four parts. They are name of the method, type of object or primitive type the method returns, a list of parameters and the body of the method.
A method's signature is a combination of the first three parts mentioned above.
6) What is calling method?
Ans: Calling methods are similar to calling or referring to an instance variable. These methods are accessed using dot notation.
Ex: obj.methodname(param1,param2)
7) Which method is used to determine the class of an object?
Ans: getClass( ) method can be used to find out what class the belongs to. This class is defined in the object class and is available to all objects.
8) All the classes in java.lang package are automatically imported when
a program is compiled.
a)True
b)False
Ans: a.
9) How can class be imported to a program?
Ans: To import a class, the import keyword should be used as shown.;
import classname;
10) How can class be imported from a package to a program?
Ans: import java . packagename . classname (or) import java.package name.*;
11) What is a constructor?
Ans: A constructor is a special kind of method that determines how an object is
initialized when created.
12) Which keyword is used to create an instance of a class?
Ans: new.
13) Which method is used to garbage collect an object?
Ans: finalize ().
14) Constructors can be overloaded like regular methods.
a)True
b)False
Ans: a.
15) What is casting?
Ans: Casting is bused to convert the value of one type to another.
16) Casting between primitive types allows conversion of one primitive type to another.
a)True
b)False
Ans: a.
17) Casting occurs commonly between numeric types.
a)True
b)False
Ans: a.
18) Boolean values can be cast into any other primitive type.
a)True
b)False
Ans: b.
19) Casting does not affect the original object or value.
a)True
b)False
Ans: a.
20) Which cast must be used to convert a larger value into a smaller one?
Ans: Explicit cast.
21) Which cast must be used to cast an object to another class?
Ans: Specific cast.
22) Which of the following features are common to both Java & C++?
A.The class declaration
b.The access modifiers
c.The encapsulation of data & methods with in objects
d.The use of pointers
Ans: a,b,c.
23) Which of the following statements accurately describe the use of access modifiers within a class definition?
a.They can be applied to both data & methods
b.They must precede a class's data variables or methods
c.They can follow a class's data variables or methods
d.They can appear in any order
e.They must be applied to data variables first and then to methods
Ans: a,b,d.
24) Suppose a given instance variable has been declared private.
Can this instance variable be manipulated by methods out side its class?
a.yes
b.no
Ans: b.
25) Which of the following statements can be used to describe a public method?
a.It is accessible to all other classes in the hierarchy
b.It is accessablde only to subclasses of its parent class
c.It represents the public interface of its class
d.The only way to gain access to this method is by calling one of the public class
methods
Ans: a,c.
26) Which of the following types of class members can be part of the internal part of a class?
a.Public instance variables
b.Private instance variables
c.Public methods
d.Private methods
Ans: b,d.
27) You would use the ____ operator to create a single instance of a named class.
a.new
b.dot
Ans: a.
28) Which of the following statements correctly describes the relation between an object and the instance variable it stores?
a.Each new object has its own distinctive set of instance variables
b.Each object has a copy of the instance variables of its class
c.the instance variable of each object are seperate from the variables of other objects
d.The instance variables of each object are stored together with the variables of other objects
Ans: a,b,c.
29) If no input parameters are specified in a method declaration then the declaration will include __.
a.an empty set of parantheses
b.the term void
Ans: a.
30) What are the functions of the dot(.) operator?
a.It enables you to access instance variables of any objects within a class
b.It enables you to store values in instance variables of an object
c.It is used to call object methods
d.It is to create a new object
Ans: a,b,c.
31) Which of the following can be referenced by this variable?
a.The instance variables of a class only
b.The methods of a class only
c.The instance variables and methods of a class
Ans: c.
32) The this reference is used in conjunction with ___methods.
a.static
b.non-static
Ans: b.
33) Which of the following operators are used in conjunction with the this and super references?
a.The new operator
b.The instanceof operator
c.The dot operator
Ans: c.
34) A constructor is automatically called when an object is instantiated
a. true
b. false
Ans: a.
35) When may a constructor be called without specifying arguments?
a. When the default constructor is not called
b. When the name of the constructor differs from that of the class
c. When there are no constructors for the class
Ans: c.
36) Each class in java can have a finalizer method
a. true
b.false
Ans: a.
37) When an object is referenced, does this mean that it has been identified by the finalizer method for garbage collection?
a.yes
b.no
Ans: b.
38) Because finalize () belongs to the java.lang.Object class, it is present in all ___.
a.objects
b.classes
c.methods
Ans: b.
39) Identify the true statements about finalization.
a.A class may have only one finalize method
b.Finalizers are mostly used with simple classes
c.Finalizer overloading is not allowed
Ans: a,c.
40) When you write finalize() method for your class, you are overriding a finalizer
inherited from a super class.
a.true
b.false
Ans: a.
41) Java memory management mechanism garbage collects objects which are no longer referenced
a true
b.false
Ans: a.
42) are objects referenced by a variable candidates for garbage collection when the variable goes out of scope?
a yes
b. no
Ans: a.
43) Java's garbage collector runs as a ___ priority thread waiting for __priority threads to relinquish the processor.
a.high
b.low
Ans: a,b.
44) The garbage collector will run immediately when the system is out of memory
a.true
b.false
Ans: a.
45) You can explicitly drop a object reference by setting the value of a variable whose data type is a reference type to ___
Ans: null
46) When might your program wish to run the garbage collecter?
a. before it enters a compute-intense section of code
b. before it enters a memory-intense section of code
c. before objects are finalized
d. when it knows there will be some idle time
Ans: a,b,d
47) For externalizable objects the class is solely responsible for the external format of its contents
a.true
b.false
Ans: a
48) When an object is stored, are all of the objects that are reachable from that object stored as well?
a.true
b.false
Ans: a
49) The default__ of objects protects private and trancient data, and supports the __ of the classes
a.evolution
b.encoding
Ans: b,a.
50) Which are keywords in Java?
a) NULL
b) sizeof
c) friend
d) extends
e) synchronized
Ans : d and e
51) When must the main class and the file name coincide?
Ans :When class is declared public.
52) What are different modifiers?
Ans : public, private, protected, default, static, trancient, volatile, final, abstract.
53) What are access modifiers?
Ans : public, private, protected, default.
54) What is meant by "Passing by value" and " Passing by reference"?
Ans : objects – pass by referrence
Methods - pass by value
55) Is a class a subclass of itself?
Ans : A class is a subclass itself.
56) What modifiers may be used with top-level class?
Ans : public, abstract, final.
57) What is an example of polymorphism?
Inner class
Anonymous classes
Method overloading
Method overriding
Ans : c
Packages and interface
1) What are packages ? what is use of packages ?
Ans :The package statement defines a name space in which classes are stored.If you omit the package, the classes are put into the default package.
Signature... package pkg;
Use: * It specifies to which package the classes defined in a file belongs to. * Package is both naming and a visibility control mechanism.
2) What is difference between importing "java.applet.Applet" and "java.applet.*;" ?
Ans :"java.applet.Applet" will import only the class Applet from the package java.applet
Where as "java.applet.*" will import all the classes from java.applet package.
3) What do you understand by package access specifier?
Ans : public: Anything declared as public can be accessed from anywhere
private: Anything declared in the private can’t be seen outside of its class.
default: It is visible to subclasses as well as to other classes in the same package.
4) What is interface? What is use of interface?
Ans : It is similar to class which may contain method’s signature only but not bodies.
Methods declared in interface are abstract methods. We can implement many interfaces on a class which support the multiple inheritance.
5) Is it is necessary to implement all methods in an interface?
Ans : Yes. All the methods have to be implemented.
6) Which is the default access modifier for an interface method?
Ans : public.
7) Can we define a variable in an interface ?and what type it should be ?
Ans : Yes we can define a variable in an interface. They are implicitly final and static.
8) What is difference between interface and an abstract class?
Ans : All the methods declared inside an Interface are abstract. Where as abstract class must have at least one abstract method and others may be concrete or abstract.
In Interface we need not use the keyword abstract for the methods.
9) By default, all program import the java.lang package.
True/False
Ans : True
10) Java compiler stores the .class files in the path specified in CLASSPATH
environmental variable.
True/False
Ans : False
11) User-defined package can also be imported just like the standard packages.
True/False
Ans : True
12) When a program does not want to handle exception, the ______class is used.
Ans : Throws
13) The main subclass of the Exception class is _______ class.
Ans : RuntimeException
14) Only subclasses of ______class may be caught or thrown.
Ans : Throwable
15) Any user-defined exception class is a subclass of the _____ class.
Ans : Exception
16) The catch clause of the user-defined exception class should ______ its
Base class catch clause.
Ans : Exception
17) A _______ is used to separate the hierarchy of the class while declaring an
Import statement.
Ans : Package
18) All standard classes of Java are included within a package called _____.
Ans : java.lang
19) All the classes in a package can be simultaneously imported using ____.
Ans : *
20) Can you define a variable inside an Interface. If no, why? If yes, how?
Ans.: YES. final and static
21) How many concrete classes can you have inside an interface?
Ans.: None
22) Can you extend an interface?
Ans.: Yes
23) Is it necessary to implement all the methods of an interface while implementing the interface?
Ans.: No
24) If you do not implement all the methods of an interface while implementing , what specifier should you use for the class ?
Ans.: abstract
25) How do you achieve multiple inheritance in Java?
Ans: Using interfaces.
26) How to declare an interface example?
Ans : access class classname implements interface.
27) Can you achieve multiple interface through interface?
a)True
b) false
Ans : a.
28) Can variables be declared in an interface ? If so, what are the modifiers?
Ans : Yes. final and static are the modifiers can be declared in an interface.
29) What are the possible access modifiers when implementing interface methods?
Ans : public.
30) Can anonymous classes be implemented an interface?
Ans : Yes.
31) Interfaces can’t be extended.
a)True
b)False
Ans : b.
32) Name interfaces without a method?
Ans : Serializable, Cloneble & Remote.
33) Is it possible to use few methods of an interface in a class ? If so, how?
Ans : Yes. Declare the class as abstract.
Exception Handling
1) What is the difference between ‘throw’ and ‘throws’ ?And it’s application?
Ans : Exceptions that are thrown by java runtime systems can be handled by Try and catch blocks. With throw exception we can handle the exceptions thrown by the program itself. If a method is capable of causing an exception that it does not
handle, it must specify this behavior so the callers of the method can guard
against that exception.
2) What is the difference between ‘Exception’ and ‘error’ in java?
Ans : Exception and Error are the subclasses of the Throwable class. Exception class is used for exceptional conditions that user program should catch. With exception class we can subclass to create our own custom exception.
Error defines exceptions that are not excepted to be caught by you program. Example is Stack Overflow.
3) What is ‘Resource leak’?
Ans : Freeing up other resources that might have been allocated at the beginning of a method.
4)What is the ‘finally’ block?
Ans : Finally block will execute whether or not an exception is thrown. If an exception is thrown, the finally block will execute even if no catch statement match the exception. Any time a method is about to return to the caller from inside try/catch block, via an uncaught exception or an explicit return statement, the finally clause is also execute.
5) Can we have catch block with out try block? If so when?
Ans : No. Try/Catch or Try/finally form a unit.
6) What is the difference between the following statements?
Catch (Exception e),
Catch (Error err),
Catch (Throwable t)
Ans :
7) What will happen to the Exception object after exception handling?
Ans : It will go for Garbage Collector. And frees the memory.
8) How many Exceptions we can define in ‘throws’ clause?
Ans : We can define multiple exceptions in throws clause.
Signature is..
type method-name (parameter-list) throws exception-list
9) The finally block is executed when an exception is thrown, even if no catch matches it.
True/False
Ans : True
10) The subclass exception should precede the base class exception when used within the catch clause.
True/False
Ans : True
11) Exceptions can be caught or rethrown to a calling method.
True/False
Ans : True
12) The statements following the throw keyword in a program are not executed.
True/False
Ans : True
13) The toString ( ) method in the user-defined exception class is overridden.
True/False
Ans : True
MULTI THREADING
1) What are the two types of multitasking?
Ans : 1.process-based
2.Thread-based
2) What are the two ways to create the thread?
Ans : 1.by implementing Runnable
2.by extending Thread
3) What is the signature of the constructor of a thread class?
Ans : Thread(Runnable threadob,String threadName)
4) What are all the methods available in the Runnable Interface?
Ans : run()
5) What is the data type for the method isAlive() and this method is
available in which class?
Ans : boolean, Thread
6) What are all the methods available in the Thread class?
Ans : 1.isAlive()
2.join()
3.resume()
4.suspend()
5.stop()
6.start()
7.sleep()
8.destroy()
7) What are all the methods used for Inter Thread communication and what is the class in which these methods are defined?
Ans :1. wait(),notify() & notifyall()
2. Object class
8) What is the mechanisam defind by java for the Resources to be used by only one Thread at a time?
Ans : Synchronisation
9) What is the procedure to own the moniter by many threads?
Ans : not possible
10) What is the unit for 1000 in the below statement?
ob.sleep(1000)
Ans : long milliseconds
11) What is the data type for the parameter of the sleep() method?
Ans : long
12) What are all the values for the following level?
max-priority
min-priority
normal-priority
Ans : 10,1,5
13) What is the method available for setting the priority?
Ans : setPriority()
14) What is the default thread at the time of starting the program?
Ans : main thread
15) The word synchronized can be used with only a method.
True/ False
Ans : False
16) Which priority Thread can prompt the lower primary Thread?
Ans : Higher Priority
17) How many threads at a time can access a monitor?
Ans : one
18) What are all the four states associated in the thread?
Ans : 1. new 2. runnable 3. blocked 4. dead
19) The suspend()method is used to teriminate a thread?
True /False
Ans : False
20) The run() method should necessary exists in clases created as subclass of thread?
True /False
Ans : True
21) When two threads are waiting on each other and can't proceed the programe is said to be in a deadlock?
True/False
Ans : True
22) Which method waits for the thread to die ?
Ans : join() method
23) Which of the following is true?
1) wait(),notify(),notifyall() are defined as final & can be called only from with in a synchronized method
2) Among wait(),notify(),notifyall() the wait() method only throws IOException
3) wait(),notify(),notifyall() & sleep() are methods of object class
1
2
3
1 & 2
1,2 & 3
Ans : D
24) Garbage collector thread belongs to which priority?
Ans : low-priority
25) What is meant by timeslicing or time sharing?
Ans : Timeslicing is the method of allocating CPU time to individual threads in a priority schedule.
26) What is meant by daemon thread? In java runtime, what is it's role?
Ans : Daemon thread is a low priority thread which runs intermittently in the background doing the garbage collection operation for the java runtime system.
Inheritance
1) What is the difference between superclass & subclass?
Ans : A super class is a class that is inherited whereas subclass is a class that does the inheriting.
2) Which keyword is used to inherit a class?
Ans : extends
3) Subclasses methods can access superclass members/ attributes at all times?
True/False
Ans : False
4) When can subclasses not access superclass members?
Ans : When superclass is declared as private.
5) Which class does begin Java class hierarchy?
Ans : Object class
6) Object class is a superclass of all other classes?
True/False
Ans : True
7) Java supports multiple inheritance?
True/False
Ans : False
8) What is inheritance?
Ans : Deriving an object from an existing class. In the other words, Inheritance is the process of inheriting all the features from a class
9) What are the advantages of inheritance?
Ans : Reusability of code and accessibility of variables and methods of the superclass by subclasses.
10) Which method is used to call the constructors of the superclass from the subclass?
Ans : super(argument)
11) Which is used to execute any method of the superclass from the subclass?
Ans : super.method-name(arguments)
12) Which methods are used to destroy the objects created by the constructor methods?
Ans : finalize()
13) What are abstract classes?
Ans : Abstract classes are those for which instances can’t be created.
14) What must a class do to implement an interface?
Ans: It must provide all of the methods in the interface and identify the interface in its implements clause.
15) Which methods in the Object class are declared as final?
Ans : getClass(), notify(), notifyAll(), and wait()
16) Final methods can be overridden.
True/False
Ans : False
17) Declaration of methods as final results in faster execution of the program?
True/False
Ans: True
18) Final variables should be declared in the beginning?
True/False
Ans : True
19) Can we declare variable inside a method as final variables? Why?
Ans : Cannot because, local variable cannot be declared as final variables.
20) Can an abstract class may be final?
Ans : An abstract class may not be declared as final.
21) Does a class inherit the constructors of it's super class?
Ans: A class does not inherit constructors from any of it's super classes.
22) What restrictions are placed on method overloading?
Ans: Two methods may not have the same name and argument list but different return types.
23) What restrictions are placed on method overriding?
Ans : Overridden methods must have the same name , argument list , and return type. The overriding method may not limit the access of the method it overridees.The overriding method may not throw any exceptions that may not be thrown by the overridden method.
24) What modifiers may be used with an inner class that is a member of an outer class?
Ans : a (non-local) inner class may be declared as public, protected, private, static, final or abstract.
25) How this() is used with constructors?
Ans: this() is used to invoke a constructor of the same class
26) How super() used with constructors?
Ans : super() is used to invoke a super class constructor
27) Which of the following statements correctly describes an interface?
a)It's a concrete class
b)It's a superclass
c)It's a type of abstract class
Ans: c
28) An interface contains __ methods
a)Non-abstract
b)Implemented
c)unimplemented
Ans:c
STRING HANDLING
Which package does define String and StringBuffer classes?
Ans : java.lang package.
Which method can be used to obtain the length of the String?
Ans : length( ) method.
How do you concatenate Strings?
Ans : By using " + " operator.
Which method can be used to compare two strings for equality?
Ans : equals( ) method.
Which method can be used to perform a comparison between strings that ignores case differences?
Ans : equalsIgnoreCase( ) method.
What is the use of valueOf( ) method?
Ans : valueOf( ) method converts data from its internal format into a human-readable form.
What are the uses of toLowerCase( ) and toUpperCase( ) methods?
Ans : The method toLowerCase( ) converts all the characters in a string from uppercase to
lowercase.
The method toUpperCase( ) converts all the characters in a string from lowercase to
uppercase.
Which method can be used to find out the total allocated capacity of a StrinBuffer?
Ans : capacity( ) method.
Which method can be used to set the length of the buffer within a StringBuffer object?
Ans : setLength( ).
What is the difference between String and StringBuffer?
Ans : String objects are constants, whereas StringBuffer objects are not.
String class supports constant strings, whereas StringBuffer class supports growable, modifiable strings.
What are wrapper classes?
Ans : Wrapper classes are classes that allow primitive types to be accessed as objects.
Which of the following is not a wrapper class?
String
Integer
Boolean
Character
Ans : a.
What is the output of the following program?
public class Question {
public static void main(String args[]) {
String s1 = "abc";
String s2 = "def";
String s3 = s1.concat(s2.toUpperCase( ) );
System.out.println(s1+s2+s3);
}
}
abcdefabcdef
abcabcDEFDEF
abcdefabcDEF
None of the above
ANS : c.
Which of the following methods are methods of the String class?
delete( )
append( )
reverse( )
replace( )
Ans : d.
Which of the following methods cause the String object referenced by s to be changed?
s.concat( )
s.toUpperCase( )
s.replace( )
s.valueOf( )
Ans : a and b.
String is a wrapper class?
True
False
Ans : b.
17) If you run the code below, what gets printed out?
String s=new String("Bicycle");
int iBegin=1;
char iEnd=3;
System.out.println(s.substring(iBegin,iEnd));
Bic
ic
c) icy
d) error: no method matching substring(int,char)
Ans : b.
18) Given the following declarations
String s1=new String("Hello")
String s2=new String("there");
String s3=new String();
Which of the following are legal operations?
s3=s1 + s2;
s3=s1 - s2;
c) s3=s1 & s2
d) s3=s1 && s2
Ans : a.
19) Which of the following statements are true?
The String class is implemented as a char array, elements are addressed using the stringname[] convention
b) Strings are a primitive type in Java that overloads the + operator for concatenation
c) Strings are a primitive type in Java and the StringBuffer is used as the matching wrapper type
d) The size of a string can be retrieved using the length property.
Ans : b.
EXPLORING JAVA.LANG
java.lang package is automatically imported into all programs.
True
False
Ans : a
What are the interfaces defined by java.lang?
Ans : Cloneable, Comparable and Runnable.
What are the constants defined by both Flaot and Double classes?
Ans : MAX_VALUE,
MIN_VALUE,
NaN,
POSITIVE_INFINITY,
NEGATIVE_INFINITY and
TYPE.
What are the constants defined by Byte, Short, Integer and Long?
Ans : MAX_VALUE,
MIN_VALUE and
TYPE.
What are the constants defined by both Float and Double classes?
Ans : MAX_RADIX,
MIN_RADIX,
MAX_VALUE,
MIN_VALUE and
TYPE.
What is the purpose of the Runtime class?
Ans : The purpose of the Runtime class is to provide access to the Java runtime system.
What is the purpose of the System class?
Ans : The purpose of the System class is to provide access to system resources.
Which class is extended by all other classes?
Ans : Object class is extended by all other classes.
Which class can be used to obtain design information about an object?
Ans : The Class class can be used to obtain information about an object’s design.
Which method is used to calculate the absolute value of a number?
Ans : abs( ) method.
What are E and PI?
Ans : E is the base of the natural logarithm and PI is the mathematical value pi.
Which of the following classes is used to perform basic console I/O?
System
SecurityManager
Math
Runtime
Ans : a.
Which of the following are true?
The Class class is the superclass of the Object class.
The Object class is final.
The Class class can be used to load other classes.
The ClassLoader class can be used to load other classes.
Ans : c and d.
Which of the following methods are methods of the Math class?
absolute( )
log( )
cosine( )
sine( )
Ans : b.
Which of the following are true about the Error and Exception classes?
Both classes extend Throwable.
The Error class is final and the Exception class is not.
The Exception class is final and the Error is not.
Both classes implement Throwable.
Ans : a.
Which of the following are true?
The Void class extends the Class class.
The Float class extends the Double class.
The System class extends the Runtime class.
The Integer class extends the Number class.
Ans : d.
17) Which of the following will output -4.0
System.out.println(Math.floor(-4.7));
System.out.println(Math.round(-4.7));
System.out.println(Math.ceil(-4.7));
d) System.out.println(Math.Min(-4.7));
Ans : c.
18) Which of the following are valid statements
a) public class MyCalc extends Math
b) Math.max(s);
c) Math.round(9.99,1);
d) Math.mod(4,10);
e) None of the above.
Ans : e.
19) What will happen if you attempt to compile and run the following code?
Integer ten=new Integer(10);
Long nine=new Long (9);
System.out.println(ten + nine);
int i=1;
System.out.println(i + ten);
19 followed by 20
19 followed by 11
Error: Can't convert java lang Integer
d) 10 followed by 1
Ans : c.
INPUT / OUTPUT : EXPLORING JAVA.IO
What is meant by Stream and what are the types of Streams and classes of the Streams?
Ans : A Stream is an abstraction that either produces or consumes information.
There are two types of Streams. They are:
Byte Streams : Byte Streams provide a convenient means for handling input and output of bytes.
Character Streams : Character Streams provide a convenient means for handling input and output of characters.
Byte Stream classes : Byte Streams are defined by using two abstract classes. They are:InputStream and OutputStream.
Character Stream classes : Character Streams are defined by using two abstract classes. They are : Reader and Writer.
Which of the following statements are true?
UTF characters are all 8-bits.
UTF characters are all 16-bits.
UTF characters are all 24-bits.
Unicode characters are all 16-bits.
Bytecode characters are all 16-bits.
Ans : d.
Which of the following statements are true?
When you construct an instance of File, if you do not use the filenaming semantics of the local machine, the constructor will throw an IOException.
When you construct an instance of File, if the corresponding file does not exist on the local file system, one will be created.
When an instance of File is garbage collected, the corresponding file on the local file system is deleted.
None of the above.
Ans : a,b and c.
The File class contains a method that changes the current working directory.
True
False
Ans : b.
It is possible to use the File class to list the contents of the current working directory.
True
False
Ans : a.
Readers have methods that can read and return floats and doubles.
True
False
Ans : b.
You execute the code below in an empty directory. What is the result?
File f1 = new File("dirname");
File f2 = new File(f1, "filename");
A new directory called dirname is created in the current working directory.
A new directory called dirname is created in the current working directory. A new file called filename is created in directory dirname.
A new directory called dirname and a new file called filename are created, both in the current working directory.
A new file called filename is created in the current working directory.
No directory is created, and no file is created.
Ans : e.
What is the difference between the Reader/Writer class hierarchy and the
InputStream/OutputStream class hierarchy?
Ans : The Reader/Writer class hierarchy is character-oriented and the InputStream/OutputStream class hierarchy is byte-oriented.
What is an I/O filter?
Ans : An I/O filter is an object that reads from one stream and writes to another, usually altering the data in some way as it is passed from one stream to another.
What is the purpose of the File class?
Ans : The File class is used to create objects that provide access to the files and directories of a local file system.
What interface must an object implement before it can be written to a stream as an object?
Ans : An object must implement the Serializable or Externalizable interface before it can be written to a stream as an object.
What is the difference between the File and RandomAccessFile classes?
Ans : The File class encapsulates the files and directories of the local file system. The RandomAccessFile class provides the methods needed to directly access data contained in any part of a file.
What class allows you to read objects directly from a stream?
Ans : The ObjectInputStream class supports the reading of objects from input streams.
What value does read( ) return when it has reached the end of a file?
Ans : The read( ) method returns – 1 when it has reached the end of a file.
What value does readLine( ) return when it has reached the end of a file?
Ans : The readLine( ) method returns null when it has reached the end of a file.
How many bits are used to represent Unicode, ASCII, UTF-16 and UTF-8 characters?
Ans : Unicode requires 16-bits and ASCII requires 8-bits. Although the ASCII character set uses only 1-bits, it is usually represented as 8-bits. UTF-8 represents characters using 8, 16 and 18-bit patterns. UTF-16 uses 16-bit and larger bit patterns.
Which of the following are true?
The InputStream and OutputStream classes are byte-oriented.
The ObjectInputStream and ObjectOutputStream do not support serialized object input and output.
The Reader and Writer classes are character-oriented.
The Reader and Writer classes are the preferred solution to serialized object output.
Ans : a and c.
Which of the following are true about I/O filters?
Filters are supported on input, but not on output.
Filters are supported by the InputStream/OutputStream class hierarchy, but not by the Reader/Writer class hierarchy.
Filters read from one stream and write to another.
A filter may alter data that is read from one stream and written to another.
Ans : c and d.
Which of the following are true?
Any Unicode character is represented using 16-bits.
7-bits are needed to represent any ASCII character.
UTF-8 characters are represented using only 8-bits.
UTF-16 characters are represented using only 16-bits.
Ans : a and b.
Which of the following are true?
The Serializable interface is used to identify objects that may be written to an output stream.
The Externalizable interface is implemented by classes that control the way in which their objects are serialized.
The Serializable interface extends the Externalizable interface.
The Externalizable interface extends the Serializable interface.
Ans : a, b and d.
Which of the following are true about the File class?
A File object can be used to change the current working directory.
A File object can be used to access the files in the current directory.
When a File object is created, a corresponding directory or file is created in the local file system.
File objects are used to access files and directories on the local file system.
File objects can be garbage collected.
When a File object is garbage collected, the corresponding file or directory is deleted.
Ans : b, d and e.
How do you create a Reader object from an InputStream object?
Use the static createReader( ) method of InputStream class.
Use the static createReader( ) method of Reader class.
Create an InputStreamReader object, passing the InputStream object as an argument to the InputStreamReader constructor.
Create an OutputStreamReader object, passing the InputStream object as an argument to the OutputStreamReader constructor.
Ans : c.
Which of the following are true?
Writer classes can be used to write characters to output streams using different character encodings.
Writer classes can be used to write Unicode characters to output streams.
Writer classes have methods that support the writing of the values of any Java primitive type to output streams.
Writer classes have methods that support the writing of objects to output streams.
Ans : a and b.
The isFile( ) method returns a boolean value depending on whether the file object is a file or a directory.
True.
False.
Ans : a.
Reading or writing can be done even after closing the input/output source.
True.
False.
Ans : b.
The ________ method helps in clearing the buffer.
Ans : flush( ).
The System.err method is used to print error message.
True.
False.
Ans : a.
What is meant by StreamTokenizer?
Ans : StreamTokenizer breaks up InputStream into tokens that are delimited by sets of characters.
It has the constructor : StreamTokenizer(Reader inStream).
Here inStream must be some form of Reader.
What is Serialization and deserialization?
Ans : Serialization is the process of writing the state of an object to a byte stream.
Deserialization is the process of restoring these objects.
30) Which of the following can you perform using the File class?
a) Change the current directory
b) Return the name of the parent directory
c) Delete a file
d) Find if a file contains text or binary information
Ans : b and c.
31)How can you change the current working directory using an instance of the File class called FileName?
FileName.chdir("DirName").
FileName.cd("DirName").
FileName.cwd("DirName").
The File class does not support directly changing the current directory.
Ans : d.
EVENT HANDLING
The event delegation model, introduced in release 1.1 of the JDK, is fully compatible with the
event model.
True
False
Ans : b.
A component subclass that has executed enableEvents( ) to enable processing of a certain kind of event cannot also use an adapter as a listener for the same kind of event.
True
False
Ans : b.
What is the highest-level event class of the event-delegation model?
Ans : The java.util.eventObject class is the highest-level class in the event-delegation hierarchy.
What interface is extended by AWT event listeners?
Ans : All AWT event listeners extend the java.util.EventListener interface.
What class is the top of the AWT event hierarchy?
Ans : The java.awt.AWTEvent class is the highest-level class in the AWT event class hierarchy.
What event results from the clicking of a button?
Ans : The ActionEvent event is generated as the result of the clicking of a button.
What is the relationship between an event-listener interface and an event-adapter class?
Ans : An event-listener interface defines the methods that must be implemented by an event
handler for a particular kind of event.
An event adapter provides a default implementation of an event-listener interface.
In which package are most of the AWT events that support the event-delegation model defined?
Ans : Most of the AWT–related events of the event-delegation model are defined in the
java.awt.event package. The AWTEvent class is defined in the java.awt package.
What is the advantage of the event-delegation model over the earlier event-inheritance model?
Ans : The event-delegation has two advantages over the event-inheritance model. They are :
It enables event handling by objects other than the ones that generate the events. This
allows a clean separation between a component’s design and its use.
It performs much better in applications where many events are generated. This
performance improvement is due to the fact that the event-delegation model does not
have to repeatedly process unhandled events, as is the case of the event-inheritance
model.
What is the purpose of the enableEvents( ) method?
Ans :The enableEvents( ) method is used to enable an event for a particular object.
Which of the following are true?
The event-inheritance model has replaced the event-delegation model.
The event-inheritance model is more efficient than the event-delegation model.
The event-delegation model uses event listeners to define the methods of event-handling classes.
The event-delegation model uses the handleEvent( ) method to support event handling.
Ans : c.
Which of the following is the highest class in the event-delegation model?
java.util.EventListener
java.util.EventObject
java.awt.AWTEvent
java.awt.event.AWTEvent
Ans : b.
When two or more objects are added as listeners for the same event, which listener is first invoked to handle the event?
The first object that was added as listener.
The last object that was added as listener.
There is no way to determine which listener will be invoked first.
It is impossible to have more than one listener for a given event.
Ans : c.
Which of the following components generate action events?
Buttons
Labels
Check boxes
Windows
Ans : a.
Which of the following are true?
A TextField object may generate an ActionEvent.
A TextArea object may generate an ActionEvent.
A Button object may generate an ActionEvent.
A MenuItem object may generate an ActionEvent.
Ans : a,c and d.
Which of the following are true?
The MouseListener interface defines methods for handling mouse clicks.
The MouseMotionListener interface defines methods for handling mouse clicks.
The MouseClickListener interface defines methods for handling mouse clicks.
The ActionListener interface defines methods for handling the clicking of a button.
Ans : a and d.
Suppose that you want to have an object eh handle the TextEvent of a TextArea object t. How should you add eh as the event handler for t?
t.addTextListener(eh);
eh.addTextListener(t);
addTextListener(eh.t);
addTextListener(t,eh);
Ans : a.
What is the preferred way to handle an object’s events in Java 2?
Override the object’s handleEvent( ) method.
Add one or more event listeners to handle the events.
Have the object override its processEvent( ) methods.
Have the object override its dispatchEvent( ) methods.
Ans : b.
Which of the following are true?
A component may handle its own events by adding itself as an event listener.
A component may handle its own events by overriding its event-dispatching method.
A component may not handle oits own events.
A component may handle its own events only if it implements the handleEvent( ) method.
Ans : a and b.
APPLETS
What is an Applet? Should applets have constructors?
Ans : Applet is a dynamic and interactive program that runs inside a Web page
displayed by a Java capable browser. We don’t have the concept of Constructors in Applets.
How do we read number information from my applet’s parameters, given that Applet’s getParameter() method returns a string?
Ans : Use the parseInt() method in the Integer Class, the Float(String) constructor in the
Class Float, or the Double(String) constructor in the class Double.
How can I arrange for different applets on a web page to communicate with each other?
Ans : Name your applets inside the Applet tag and invoke AppletContext’s getApplet()
method in your applet code to obtain references to the other applets on the page.
How do I select a URL from my Applet and send the browser to that page?
Ans : Ask the applet for its applet context and invoke showDocument() on that context object.
Eg. URL targetURL;
String URLString
AppletContext context = getAppletContext();
try{
targetUR L = new URL(URLString);
} catch (Malformed URLException e){
// Code for recover from the exception
}
context. showDocument (targetURL);
Can applets on different pages communicate with each other?
Ans : No. Not Directly. The applets will exchange the information at one meeting place
either on the local file system or at remote system.
How do Applets differ from Applications?
Ans : Appln: Stand Alone
Applet: Needs no explicit installation on local m/c.
Appln: Execution starts with main() method.
Applet: Execution starts with init() method.
Appln: May or may not be a GUI
Applet: Must run within a GUI (Using AWT)
How do I determine the width and height of my application?
Ans : Use the getSize() method, which the Applet class inherits from the Component
class in the Java.awt package. The getSize() method returns the size of the applet as
a Dimension object, from which you extract separate width, height fields.
Eg. Dimension dim = getSize ();
int appletwidth = dim.width ();
8) What is AppletStub Interface?
Ans : The applet stub interface provides the means by which an applet and the browser communicate. Your code will not typically implement this interface.
It is essential to have both the .java file and the .html file of an applet in the same
directory.
True.
False.
Ans : b.
The <PARAM> tag contains two attributes namely _________ and _______.
Ans : Name , value.
Passing values to parameters is done in the _________ file of an applet.
Ans : .html.
12) What tags are mandatory when creating HTML to display an applet
name, height, width
code, name
codebase, height, width
d) code, height, width
Ans : d.
Applet’s getParameter( ) method can be used to get parameter values.
True.
False.
Ans : a.
What are the Applet’s Life Cycle methods? Explain them?
Ans : init( ) method - Can be called when an applet is first loaded.
start( ) method - Can be called each time an applet is started.
paint( ) method - Can be called when the applet is minimized or refreshed.
stop( ) method - Can be called when the browser moves off the applet’s page.
destroy( ) method - Can be called when the browser is finished with the applet.
What are the Applet’s information methods?
Ans : getAppletInfo( ) method : Returns a string describing the applet, its author ,copy
right information, etc.
getParameterInfo( ) method : Returns an array of string describing the applet’s parameters.
All Applets are subclasses of Applet.
True.
False.
Ans : a.
All Applets must import java.applet and java.awt.
True.
False.
Ans : a.
What are the steps involved in Applet development?
Ans : a) Edit a Java source file,
b) Compile your program and
c) Execute the appletviewer, specifying the name of your applet’s source file.
Applets are executed by the console based Java run-time interpreter.
True.
False.
Ans : b.
Which classes and interfaces does Applet class consist?
Ans : Applet class consists of a single class, the Applet class and three interfaces: AppletContext,
AppletStub and AudioClip.
What is the sequence for calling the methods by AWT for applets?
Ans : When an applet begins, the AWT calls the following methods, in this sequence.
init( )
start( )
paint( )
When an applet is terminated, the following sequence of method cals takes place :
stop( )
destroy( )
Which method is used to output a string to an applet?
Ans : drawString ( ) method.
Every color is created from an RGB value.
True.
False
Ans : a.
AWT : WINDOWS, GRAPHICS AND FONTS
How would you set the color of a graphics context called g to cyan?
g.setColor(Color.cyan);
g.setCurrentColor(cyan);
g.setColor("Color.cyan");
g.setColor("cyan’);
g.setColor(new Color(cyan));
Ans : a.
The code below draws a line. What color is the line?
g.setColor(Color.red.green.yellow.red.cyan);
g.drawLine(0, 0, 100,100);
Red
Green
Yellow
Cyan
Black
Ans : d.
What does the following code draw?
g.setColor(Color.black);
g.drawLine(10, 10, 10, 50);
g.setColor(Color.RED);
g.drawRect(100, 100, 150, 150);
A red vertical line that is 40 pixels long and a red square with sides of 150 pixels
A black vertical line that is 40 pixels long and a red square with sides of 150 pixels
A black vertical line that is 50 pixels long and a red square with sides of 150 pixels
A red vertical line that is 50 pixels long and a red square with sides of 150 pixels
A black vertical line that is 40 pixels long and a red square with sides of 100 pixel
Ans : b.
Which of the statements below are true?
A polyline is always filled.
b) A polyline can not be filled.
c) A polygon is always filled.
d) A polygon is always closed
e) A polygon may be filled or not filled
Ans : b, d and e.
What code would you use to construct a 24-point bold serif font?
new Font(Font.SERIF, 24,Font.BOLD);
new Font("SERIF", 24, BOLD");
new Font("BOLD ", 24,Font.SERIF);
new Font("SERIF", Font.BOLD,24);
new Font(Font.SERIF, "BOLD", 24);
Ans : d.
What does the following paint( ) method draw?
Public void paint(Graphics g) {
g.drawString("question #6",10,0);
}
The string "question #6", with its top-left corner at 10,0
A little squiggle coming down from the top of the component, a little way in from the left edge
Ans : b.
What does the following paint( ) method draw?
Public void paint(Graphics g) {
g.drawString("question #6",10,0);
}
A circle at (100, 100) with radius of 44
A circle at (100, 44) with radius of 100
A circle at (100, 44) with radius of 44
The code does not compile
Ans : d.
8)What is relationship between the Canvas class and the Graphics class?
Ans : A Canvas object provides access to a Graphics object via its paint( ) method.
What are the Component subclasses that support painting.
Ans : The Canvas, Frame, Panel and Applet classes support painting.
What is the difference between the paint( ) and repaint( ) method?
Ans : The paint( ) method supports painting via a Graphics object. The repaint( ) method is used
to cause paint( ) to be invoked by the AWT painting method.
What is the difference between the Font and FontMetrics classes?
Ans : The FontMetrics class is used to define implementation-specific properties, such as ascent
and descent, of a Font object.
Which of the following are passed as an argument to the paint( ) method?
A Canvas object
A Graphics object
An Image object
A paint object
Ans : b.
Which of the following methods are invoked by the AWT to support paint and repaint operations?
paint( )
repaint( )
draw( )
redraw( )
Ans : a.
Which of the following classes have a paint( ) method?
Canvas
Image
Frame
Graphics
Ans : a and c.
Which of the following are methods of the Graphics class?
drawRect( )
drawImage( )
drawPoint( )
drawString( )
Ans : a, b and d.
Which Font attributes are available through the FontMetrics class?
ascent
leading
case
height
Ans : a, b and d.
Which of the following are true?
The AWT automatically causes a window to be repainted when a portion of a window has been minimized and then maximized.
The AWT automatically causes a window to be repainted when a portion of a window has been covered and then uncovered.
The AWT automatically causes a window to be repainted when application data is changed.
The AWT does not support repainting operations.
Ans : a and b.
Which method is used to size a graphics object to fit the current size of the window?
Ans : getSize( ) method.
What are the methods to be used to set foreground and background colors?
Ans : setForeground( ) and setBackground( ) methods.
19) You have created a simple Frame and overridden the paint method as follows
public void paint(Graphics g){
g.drawString("Dolly",50,10);
}
What will be the result when you attempt to compile and run the program?
The string "Dolly" will be displayed at the centre of the frame
b) An error at compilation complaining at the signature of the paint method
c) The lower part of the word Dolly will be seen at the top of the form, with the top hidden.
d) The string "Dolly" will be shown at the bottom of the form
Ans : c.
20) Where g is a graphics instance what will the following code draw on the screen.
g.fillArc(45,90,50,50,90,180);
a) An arc bounded by a box of height 45, width 90 with a centre point of 50,50, starting
at an angle of 90 degrees traversing through 180 degrees counter clockwise.
b) An arc bounded by a box of height 50, width 50, with a centre point of 45,90 starting
at an angle of 90 degrees traversing through 180 degrees clockwise.
c) An arc bounded by a box of height 50, width 50, with a top left at coordinates of 45,
90, starting at 90 degrees and traversing through 180 degrees counter clockwise.
d) An arc starting at 45 degrees, traversing through 90 degrees clockwise bounded by a
box of height 50, width 50 with a centre point of 90, 180.
Ans : c.
21) Given the following code
import java.awt.*;
public class SetF extends Frame{
public static void main(String argv[]){
SetF s = new SetF();
s.setSize(300,200);
s.setVisible(true);
}
}
How could you set the frame surface color to pink
a)s.setBackground(Color.pink);
b)s.setColor(PINK);
c)s.Background(pink);
d)s.color=Color.pink
Ans : a.
AWT: CONTROLS, LAYOUT MANAGERS AND MENUS
What is meant by Controls and what are different types of controls?
Ans : Controls are componenets that allow a user to interact with your application.
The AWT supports the following types of controls:
Labels
Push buttons
Check boxes
Choice lists
Lists
Scroll bars
Text components
These controls are subclasses of Component.
You want to construct a text area that is 80 character-widths wide and 10 character-heights tall. What code do you use?
new TextArea(80, 10)
new TextArea(10, 80)
Ans: b.
A text field has a variable-width font. It is constructed by calling new
TextField("iiiii"). What happens if you change the contents of the text field to
"wwwww"? (Bear in mind that is one of the narrowest characters, and w is one of the widest.)
The text field becomes wider.
The text field becomes narrower.
The text field stays the same width; to see the entire contents you will have to scroll by using the ß and à keys.
The text field stays the same width; to see the entire contents you will have to scroll by using the text field’s horizontal scroll bar.
Ans : c.
The CheckboxGroup class is a subclass of the Component class.
True
False
Ans : b.
5) What are the immediate super classes of the following classes?
a) Container class
b) MenuComponent class
c) Dialog class
d) Applet class
e) Menu class
Ans : a) Container - Component
b) MenuComponent - Object
c) Dialog - Window
d) Applet - Panel
e) Menu - MenuItem
6) What are the SubClass of Textcomponent Class?
Ans : TextField and TextArea
7) Which method of the component class is used to set the position and the size of a component?
Ans : setBounds()
8) Which TextComponent method is used to set a TextComponent to the read-only state?
Ans : setEditable()
9) How can the Checkbox class be used to create a radio button?
Ans : By associating Checkbox objects with a CheckboxGroup.
10) What Checkbox method allows you to tell if a Checkbox is checked?
Ans : getState()
11) Which Component method is used to access a component's immediate Container?
getVisible()
getImmediate
getParent()
getContainer
Ans : c.
12) What methods are used to get and set the text label displayed by a Button object?
Ans : getLabel( ) and setLabel( )
13) What is the difference between a Choice and a List?
Ans : A Choice is displayed in a compact form that requires you to pull it down to see the list of available choices. Only one item may be selected from a Choice.
A List may be displayed in such a way that several List items are visible. A List supports the selection of one or more List items.
14) Which Container method is used to cause a container to be laid out and redisplayed?
Ans : validate( )
15) What is the difference between a Scollbar and a Scrollpane?
Ans : A Scrollbar is a Component, but not a Container.
A Scrollpane is a Container and handles its own events and performs its own
scrolling.
16) Which Component subclass is used for drawing and painting?
Ans : Canvas.
17) Which of the following are direct or indirect subclasses of Component?
Button
Label
CheckboxMenuItem
Toolbar
Frame
Ans : a, b and e.
18) Which of the following are direct or indirect subclasses of Container?
Frame
TextArea
MenuBar
FileDialog
Applet
Ans : a,d and e.
19) Which method is used to set the text of a Label object?
setText( )
setLabel( )
setTextLabel( )
setLabelText( )
Ans : a.
20) Which constructor creates a TextArea with 10 rows and 20 columns?
new TextArea(10, 20)
new TextArea(20, 10)
new TextArea(new Rows(10), new columns(20))
new TextArea(200)
Ans : a.
(Usage is TextArea(rows, columns)
21) Which of the following creates a List with 5 visible items and multiple selection enabled?
new List(5, true)
new List(true, 5)
new List(5, false)
new List(false,5)
Ans : a.
[Usage is List(rows, multipleMode)]
22) Which are true about the Container class?
The validate( ) method is used to cause a Container to be laid out and redisplayed.
The add( ) method is used to add a Component to a Container.
The getBorder( ) method returns information about a Container’s insets.
The getComponent( ) method is used to access a Component that is contained in a Container.
Ans : a, b and d.
23) Suppose a Panel is added to a Frame and a Button is added to the Panel. If the Frame’s font is set to 12-point TimesRoman, the Panel’s font is set to 10-point TimesRoman, and the Button’s font is not set, what font will be used to dispaly the Button’s label?
12-point TimesRoman
11-point TimesRoman
10-point TimesRoman
9-point TimesRoman
Ans : c.
A Frame’s background color is set to Color.Yellow, and a Button’s background color is to Color.Blue. Suppose the Button is added to a Panel, which is added to the Frame. What background color will be used with the Panel?
Colr.Yellow
Color.Blue
Color.Green
Color.White
Ans : a.
25) Which method will cause a Frame to be displayed?
show( )
setVisible( )
display( )
displayFrame( )
Ans : a and b.
26) All the componenet classes and container classes are derived from _________ class.
Ans : Object.
27) Which method of the container class can be used to add components to a Panel.
Ans : add ( ) method.
28) What are the subclasses of the Container class?
Ans : The Container class has three major subclasses. They are :
Window
Panel
ScrollPane
29) The Choice component allows multiple selection.
True.
False.
Ans : b.
30) The List component does not generate any events.
True.
False.
Ans : b.
31) Which components are used to get text input from the user.
Ans : TextField and TextArea.
32) Which object is needed to group Checkboxes to make them exclusive?
Ans : CheckboxGroup.
33) Which of the following components allow multiple selections?
Non-exclusive Checkboxes.
Radio buttons.
Choice.
List.
Ans : a and d.
34) What are the types of Checkboxes and what is the difference between them?
Ans : Java supports two types of Checkboxes. They are : Exclusive and Non-exclusive.
In case of exclusive Checkboxes, only one among a group of items can be selected at a time. I f an item from the group is selected, the checkbox currently checked is deselected and the new selection is highlighted. The exclusive Checkboxes are also called as Radio buttons.
The non-exclusive checkboxes are not grouped together and each one can be selected independent of the other.
35) What is a Layout Manager and what are the different Layout Managers available in java.awt and what is the default Layout manager for the panal and the panal subclasses?
Ans: A layout Manager is an object that is used to organize components in a container.
The different layouts available in java.awt are :
FlowLayout, BorderLayout, CardLayout, GridLayout and GridBag Layout.
The default Layout Manager of Panal and Panal sub classes is FlowLayout".
36) Can I exert control over the size and placement of components in my interface?
Ans : Yes.
myPanal.setLayout(null);
myPanal.setbounds(20,20,200,200);
37) Can I add the same component to more than one container?
Ans : No. Adding a component to a container automatically removes it from any previous parent(container).
38) How do I specify where a window is to be placed?
Ans : Use setBounds, setSize, or setLocation methods to implement this.
setBounds(int x, int y, int width, int height)
setBounds(Rectangle r)
setSize(int width, int height)
setSize(Dimension d)
setLocation(int x, int y)
setLocation(Point p)
39) How can we create a borderless window?
Ans : Create an instance of the Window class, give it a size, and show it on the screen.
eg. Frame aFrame = ......
Window aWindow = new Window(aFrame);
aWindow.setLayout(new FlowLayout());
aWindow.add(new Button("Press Me"));
aWindow.getBounds(50,50,200,200);
aWindow.show();
40) Can I create a non-resizable windows? If so, how?
Ans: Yes. By using setResizable() method in class Frame.
41) What is the default Layout Manager for the Window and Window subclasses (Frame,Dialog)?
Ans : BorderLayout().
42) How are the elements of different layouts organized?
Ans : FlowLayout : The elements of a FlowLayout are organized in a top to bottom, left to right fashion.
BorderLayout : The elements of a BorderLayout are organized at the
borders (North, South, East and West) and the center of a
container.
CardLayout : The elements of a CardLayout are stacked, one on top of the other, like a deck of cards.
GridLayout : The elements of a GridLayout are of equal size and are laid out using the square of a grid.
GridBagLayout : The elements of a GridBagLayout are organized according to a grid.However, the elements are of different sizes and may occupy
more than one row or column of the grid. In addition, the rows and columns may have different sizes.
43) Which containers use a BorderLayout as their default layout?
Ans : The Window, Frame and Dialog classes use a BorderLayout as their default layout.
44) Which containers use a FlowLayout as their default layout?
Ans : The Panel and the Applet classes use the FlowLayout as their default layout.
45) What is the preferred size of a component?
Ans : The preferred size of a component size that will allow the component to display normally.
46) Which method is method to set the layout of a container?
startLayout( )
initLayout( )
layoutContainer( )
setLayout( )
Ans : d.
47) Which method returns the preferred size of a component?
getPreferredSize( )
getPreferred( )
getRequiredSize( )
getLayout( )
Ans : a.
48) Which layout should you use to organize the components of a container in a
tabular form?
CardLayout
BorederLayout
FlowLayout
GridLayout
Ans : d.
An application has a frame that uses a Border layout manager. Why is it probably not a good idea to put a vertical scroll bar at North in the frame?
The scroll bar’s height would be its preferred height, which is not likely to be enough.
The scroll bar’s width would be the entire width of the frame, which would be much wider than necessary.
Both a and b.
Neither a nor b. There is no problem with the layout as described.
Ans : c.
What is the default layouts for a applet, a frame and a panel?
Ans : For an applet and a panel, Flow layout is the default layout, whereas Border layout is default layout for a frame.
If a frame uses a Grid layout manager and does not contain any panels, then all the components within the frame are the same width and height.
True
False.
Ans : a.
If a frame uses its default layout manager and does not contain any panels, then all the components within the frame are the same width and height.
True
False.
Ans : b.
With a Border layout manager, the component at Center gets all the space that is left over, after the components at North and South have been considered.
True
False
Ans : b.
An Applet has its Layout Manager set to the default of FlowLayout. What code would be the correct to change to another Layout Manager?
setLayoutManager(new GridLayout());
setLayout(new GridLayout(2,2));
c) setGridLayout(2,2,))
d setBorderLayout();
Ans : b.
55) How do you indicate where a component will be positioned using Flowlayout?
a) North, South,East,West
b) Assign a row/column grid reference
c) Pass a X/Y percentage parameter to the add method
d) Do nothing, the FlowLayout will position the component
Ans :d.
56) How do you change the current layout manager for a container?
a) Use the setLayout method
b) Once created you cannot change the current layout manager of a component
c) Use the setLayoutManager method
d) Use the updateLayout method
Ans :a.
57)When using the GridBagLayout manager, each new component requires a new instance of the GridBagConstraints class. Is this statement true or false?
a) true
b) false
Ans : b.
58) Which of the following statements are true?
a)The default layout manager for an Applet is FlowLayout
b) The default layout manager for an application is FlowLayout
c) A layout manager must be assigned to an Applet before the setSize method is called
d) The FlowLayout manager attempts to honor the preferred size of any components
Ans : a and d.
59) Which method does display the messages whenever there is an item selection or deselection of the CheckboxMenuItem menu?
Ans : itemStateChanged method.
60) Which is a dual state menu item?
Ans : CheckboxMenuItem.
61) Which method can be used to enable/diable a checkbox menu item?
Ans : setState(boolean).
Which of the following may a menu contain?
A separator
A check box
A menu
A button
A panel
Ans : a and c.
Which of the following may contain a menu bar?
A panel
A frame
An applet
A menu bar
A menu
Ans : b
64) What is the difference between a MenuItem and a CheckboxMenuItem?
Ans : The CheckboxMenuItem class extends the MenuItem class to support a menu item
that may be checked or unchecked.
65) Which of the following are true?
A Dialog can have a MenuBar.
MenuItem extends Menu.
A MenuItem can be added to a Menu.
A Menu can be added to a Menu.
Ans : c and d.
Which colour is used to indicate instance methods in the standard "javadoc" format documentation:
1) blue
2) red
3) purple
4) orange
Answer : 2
explain
In JDK 1.1 the variabels, methods and constructors are colour coded to simplifytheir identification.
endExplain
What is the correct ordering for the import, class and package declarations when found in a single file?
1) package, import, class
2) class, import, package
3) import, package, class
4) package, class, import
Answer : 1
explain
This is my explanation for question 2
endExplain
Which methods can be legally applied to a string object?
(Multiple)
1) equals(String)
2) equals(Object)
3) trim()
4) round()
5) toString()
Answer : 1,2,3,5
What is the parameter specification for the public static void main method?
(multiple)
1) String args []
2) String [] args
3) Strings args []
4) String args
Answer : 1,2
What does the zeroth element of the string array passed to the public static void main method contain?
(multiple)
1) The name of the program
2) The number of arguments
3) The first argument if one is present
Answer : 3
Which of the following are Java keywords?
(multiple)
1) goto
2) malloc
3) extends
4) FALSE
Answer : 3
What will be the result of compiling the following code:
public class Test {
public static void main (String args []) {
int age;
age = age + 1;
System.out.println("The age is " + age);
}
}
1) Compiles and runs with no output
2) Compiles and runs printing out The age is 1
3) Compiles but generates a runtime error
4) Does not compile
5) Compiles but generates a compile time error
Answer : 4
Which of these is the correct format to use to create the literal char value a?
(multiple)
1) 'a'
2) "a"
3) new Character(a)
4) \000a
Answer : 1
What is the legal range of a byte integral type?
1) 0 - 65, 535
2) (-128) - 127
3) (-32,768) - 32,767
4) (-256) - 255
Answer : 2
Which of the following is illegal:
1) int i = 32;
2) float f = 45.0;
3) double d = 45.0;
Answer 2
What will be the result of compiling the following code:
public class Test {
static int age;
public static void main (String args []) {
age = age + 1;
System.out.println("The age is " + age);
}
}
1) Compiles and runs with no output
2) Compiles and runs printing out The age is 1
3) Compiles but generates a runtime error
4) Does not compile
5) Compiles but generates a compile time error
Answer : 2
Which of the following are correct?
(multiple)
1) 128 >> 1 gives 64
2) 128 >>> 1 gives 64
3) 128 >> 1 gives -64
4) 128 >>> 1 gives -64
Answer : 1
Which of the following return true?
(multiple)
1) "john" == new String("john")
2) "john".equals("john")
3) "john" = "john"
4) "john".equals(new Button("john"))
Answer : 2
Which of the following do not lead to a runtime error?
(multiple)
1) "john" + " was " + " here"
2) "john" + 3
3) 3 + 5
4) 5 + 5.5
answer 1,2,3,4
Which of the following are so called "short circuit" logical operators?
(multiple)
1) &
2) ||
3) &&
4) |
Answer : 2,3
Which of the following are acceptable?
(multiple)
1) Object o = new Button("A");
2) Boolean flag = true;
3) Panel p = new Frame();
4) Frame f = new Panel();
5) Panel p = new Applet();
Answer : 1,5
What is the result of compiling and running the following code:
public class Test {
static int total = 10;
public static void main (String args []) {
new Test();
}
public Test () {
System.out.println("In test");
System.out.println(this);
int temp = this.total;
if (temp > 5) {
System.out.println(temp);
}
}
}
(multiple)
1) The class will not compile
2) The compiler reports and error at line 2
3) The compiler reports an error at line 9
4) The value 10 is one of the elements printed to the standard output
5) The class compiles but generates a runtime error
Answer : 4
Which of the following is correct:
1) String temp [] = new String {"j" "a" "z"};
2) String temp [] = { "j " " b" "c"};
3) String temp = {"a", "b", "c"};
4) String temp [] = {"a", "b", "c"};
Answer 4
What is the correct declaration of an abstract method that is intended to be public:
1) public abstract void add();
2) public abstract void add() {}
3) public abstract add();
4) public virtual add();
Answer : 1
Under what situations do you obtain a default constructor?
1) When you define any class
2) When the class has no other constructors
3) When you define at least one constructor
Answer : 2
Which of the following can be used to define a constructor for this class, given the following code:
public class Test {
...
}
1) public void Test() {...}
2) public Test() {...}
3) public static Test() {...}
4) public static void Test() {...}
Answer : 2
Which of the following are acceptable to the Java compiler:
(multiple)
1) if (2 == 3) System.out.println("Hi");
2) if (2 = 3) System.out.println("Hi");
3) if (true) System.out.println("Hi");
4) if (2 != 3) System.out.println("Hi");
5) if (aString.equals("hello")) System.out.println("Hi");
Answer : 1,3,4,5
Assuming a method contains code which may raise an Exception (but not a RuntimeException), what is the correct way for a method to indicate that it expects the caller to handle that exception:
1) throw Exception
2) throws Exception
3) new Exception
4) Don't need to specify anything
Answer : 2
What is the result of executing the following code, using the parameters 4 and 0:
public void divide(int a, int b) {
try {
int c = a / b;
} catch (Exception e) {
System.out.print("Exception ");
} finally {
System.out.println("Finally");
}
1) Prints out: Exception Finally
2) Prints out: Finally
3) Prints out: Exception
4) No output
Answer : 1
Which of the following is a legal return type of a method overloading the following method:
public void add(int a) {...}
1) void
2) int
3) Can be anything
Answer : 3
Which of the following statements is correct for a method which is overriding the following method:
public void add(int a) {...}
1) the overriding method must return void
2) the overriding method must return int
3) the overriding method can return whatever it likes
Answer : 1
Given the following classes defined in separate files, what will be the effect of compiling and running this class Test?
class Vehicle {
public void drive() {
System.out.println("Vehicle: drive");
}
}
class Car extends Vehicle {
public void drive() {
System.out.println("Car: drive");
}
}
public class Test {
public static void main (String args []) {
Vehicle v;
Car c;
v = new Vehicle();
c = new Car();
v.drive();
c.drive();
v = c;
v.drive();
}
}
1) Generates a Compiler error on the statement v= c;
2) Generates runtime error on the statement v= c;
3) Prints out:
Vehicle: drive
Car: drive
Car: drive
4) Prints out:
Vehicle: drive
Car: drive
Vehicle: drive
Answer : 3
Where in a constructor, can you place a call to a constructor defined in the super class?
1) Anywhere
2) The first statement in the constructor
3) The last statement in the constructor
4) You can't call super in a constructor
Answer : 2
Which variables can an inner class access from the class which encapsulates it?
(multiple)
1) All static variables
2) All final variables
3) All instance variables
4) Only final instance variables
5) Only final static variables
Answer : 1,2,3
What class must an inner class extend:
1) The top level class
2) The Object class
3) Any class or interface
4) It must extend an interface
Answer 3
In the following code, which is the earliest statement, where the object originally held in e, may be garbage collected:
1. public class Test {
2. public static void main (String args []) {
3. Employee e = new Employee("Bob", 48);
4. e.calculatePay();
5. System.out.println(e.printDetails());
6. e = null;
7. e = new Employee("Denise", 36);
8. e.calculatePay();
9. System.out.println(e.printDetails());
10. }
11. }
1) Line 10
2) Line 11
3) Line 7
4) Line 8
5) Never
Answer : 3
What is the name of the interface that can be used to define a class that can execute within its own thread?
1) Runnable
2) Run
3) Threadable
4) Thread
5) Executable
Answer : 1
What is the name of the method used to schedule a thread for execution?
1) init();
2) start();
3) run();
4) resume();
5) sleep();
Answer : 2
Which methods may cause a thread to stop executing?
(multiple)
1) sleep();
2) stop();
3) yield();
4) wait();
5) notify();
6) notifyAll()
7) synchronized()
Answer : 1,2,3,4
Which of the following would create a text field able to display 10 characters (assuming a fixed size font) displaying the initial string "hello":
1) new TextField("hello", 10);
2) new TextField("hello");
3) new textField(10);
4) new TextField();
Answer : 1
Which of the following methods are defined on the Graphics class:
(multiple)
1) drawLine(int, int, int, int)
2) drawImage(Image, int, int, ImageObserver)
3) drawString(String, int, int)
4) add(Component);
5) setVisible(boolean);
6) setLayout(Object);
Answer : 1,2,3
Which of the following layout managers honours the preferred size of a component:
(multiple)
1) CardLayout
2) FlowLayout
3) BorderLayout
4) GridLayout
Answer : 2
Given the following code what is the effect of a being 5:
public class Test {
public void add(int a) {
loop: for (int i = 1; i < 3; i++){
for (int j = 1; j < 3; j++) {
if (a == 5) {
break loop;
}
System.out.println(i * j);
}
}
}
}
1) Generate a runtime error
2) Throw an ArrayIndexOutOfBoundsException
3) Print the values: 1, 2, 2, 4
4) Produces no output
Answer : 4
What is the effect of issuing a wait() method on an object
1) If a notify() method has already been sent to that object then it has no effect
2) The object issuing the call to wait() will halt until another object sends a notify() or notifyAll() method
3) An exception will be raised
4) The object issuing the call to wait() will be automatically synchronized with any other objects using the receiving object.
Answer : 2
The layout of a container can be altered using which of the following methods:
(multiple)
1) setLayout(aLayoutManager);
2) addLayout(aLayoutManager);
3) layout(aLayoutManager);
4) setLayoutManager(aLayoutManager);
Answer : 1
Using a FlowLayout manager, which is the correct way to add elements to a container:
1) add(component);
2) add("Center", component);
3) add(x, y, component);
4) set(component);
Answer : 1
Given that a Button can generate an ActionEvent which listener would you expect to have to implement, in a class which would handle this event?
1) FocusListener
2) ComponentListener
3) WindowListener
4) ActionListener
5) ItemListener
Answer : 4
Which of the following, are valid return types, for listener methods:
1) boolean
2) the type of event handled
3) void
4) Component
Answer : 3
Assuming we have a class which implements the ActionListener interface, which method should be used to register this with a Button?
1) addListener(*);
2) addActionListener(*);
3) addButtonListener(*);
4) setListener(*);
Answer : 2
In order to cause the paint(Graphics) method to execute, which of the following is the most appropriate method to call:
1) paint()
2) repaint()
3) paint(Graphics)
4) update(Graphics)
5) None - you should never cause paint(Graphics) to execute
Answer : 2
Which of the following illustrates the correct way to pass a parameter into an applet:
1) <applet code=Test.class age=33 width=100 height=100>
2) <param name=age value=33>
3) <applet code=Test.class name=age value=33 width=100 height=100>
4) <applet Test 33>
Answer : 2
Which of the following correctly illustrate how an InputStreamReader can be created:
(multiple)
1) new InputStreamReader(new FileInputStream("data"));
2) new InputStreamReader(new FileReader("data"));
3) new InputStreamReader(new BufferedReader("data"));
4) new InputStreamReader("data");
5) new InputStreamReader(System.in);
Answer : 1,5
What is the permanent effect on the file system of writing data to a new FileWriter("report"), given the file report already exists?
1) The data is appended to the file
2) The file is replaced with a new file
3) An exception is raised as the file already exists
4) The data is written to random locations within the file
Answer : 2
What is the effect of adding the sixth element to a vector created in the following manner:
new Vector(5, 10);
1) An IndexOutOfBounds exception is raised.
2) The vector grows in size to a capacity of 10 elements
3) The vector grows in size to a capacity of 15 elements
4) Nothing, the vector will have grown when the fifth element was added
Answer : 3
What is the result of executing the following code when the value of x is 2:
switch (x) {
case 1:
System.out.println(1);
case 2:
case 3:
System.out.println(3);
case 4:
System.out.println(4);
}
1) Nothing is printed out
2) The value 3 is printed out
3) The values 3 and 4 are printed out
4) The values 1, 3 and 4 are printed out
Answer : 3
What is the result of compiling and running the Second class?
Consider the following example:
class First {
public First (String s) {
System.out.println(s);
}
}
public class Second extends First {
public static void main(String args []) {
new Second();
}
}
1) Nothing happens
2) A string is printed to the standard out
3) An instance of the class First is generated
4) An instance of the class Second is created
5) An exception is raised at runtime stating that there is no null parameter constructor in class First.
6) The class second will not compile as there is no null parameter constructor in the class First
Answer : 6
What is the result of executing the following fragment of code:
boolean flag = false;
if (flag = true) {
System.out.println("true");
} else {
System.out.println("false");
}
1) true is printed to standard out
2) false is printed to standard out
3) An exception is raised
4) Nothing happens
Answer : 1
Consider the following classes. What is the result of compiling and running this class?
public class Test {
public static void test() {
this.print();
}
public static void print() {
System.out.println("Test");
}
public static void main(String args []) {
test();
}
}
(multiple)
1) The string Test is printed to the standard out.
2) A runtime exception is raised stating that an object has not been created.
3) Nothing is printed to the standard output.
4) An exception is raised stating that the method test cannot be found.
5) An exception is raised stating that the variable this can only be used within an instance.
6) The class fails to compile stating that the variable this is undefined.
Answer : 6
Examine the following class definition:
public class Test {
public static void test() {
print();
}
public static void print() {
System.out.println("Test");
}
public void print() {
System.out.println("Another Test");
}
}
What is the result of compiling this class:
1) A successful compilation.
2) A warning stating that the class has no main method.
3) An error stating that there is a duplicated method.
4) An error stating that the method test() will call one or other of the print() methods.
Answer : 3
What is the result of compiling and executing the following Java class:
public class ThreadTest extends Thread {
public void run() {
System.out.println("In run");
suspend();
resume();
System.out.println("Leaving run");
}
public static void main(String args []) {
(new ThreadTest()).start();
}
}
1) Compilation will fail in the method main.
2) Compilation will fail in the method run.
3) A warning will be generated for method run.
4) The string "In run" will be printed to standard out.
5) Both strings will be printed to standard out.
6) Nothing will happen.
Answer : 4
Given the following sequence of Java statements, Which of the following options are true:
1. StringBuffer sb = new StringBuffer("abc");
2. String s = new String("abc");
3. sb.append("def");
4. s.append("def");
5. sb.insert(1, "zzz");
6. s.concat(sb);
7. s.trim();
(multiple)
1) The compiler would generate an error for line 1.
2) The compiler would generate an error for line 2.
3) The compiler would generate an error for line 3.
4) The compiler would generate an error for line 4.
5) The compiler would generate an error for line 5.
6) The compiler would generate an error for line 6.
7) The compiler would generate an error for line 7.
Answer : 4,6
What is the result of executing the following Java class:
import java.awt.*;
public class FrameTest extends Frame {
public FrameTest() {
add (new Button("First"));
add (new Button("Second"));
add (new Button("Third"));
pack();
setVisible(true);
}
public static void main(String args []) {
new FrameTest();
}
}
1) Nothing happens.
2) Three buttons are displayed across a window.
3) A runtime exception is generated (no layout manager specified).
4) Only the "first" button is displayed.
5) Only the "second" button is displayed.
6) Only the "third" button is displayed.
Answer : 6
Consider the following tags and attributes of tags, which can be used with the <AAPLET> and </APPLET> tags?
1. CODEBASE
2. ALT
3. NAME
4. CLASS
5. JAVAC
6. HORIZONTALSPACE
7. VERTICALSPACE
8. WIDTH
9. PARAM
10. JAR
(multiple)
1) line 1, 2, 3
2) line 2, 5, 6, 7
3) line 3, 4, 5
4) line 8, 9, 10
5) line 8, 9
Answer : 1,5
Which of the following is a legal way to construct a RandomAccessFile:
1) RandomAccessFile("data", "r");
2) RandomAccessFile("r", "data");
3) RandomAccessFile("data", "read");
4) RandomAccessFile("read", "data");
Answer : 1
Carefully examine the following code, When will the string "Hi there" be printed?
public class StaticTest {
static {
System.out.println("Hi there");
}
public void print() {
System.out.println("Hello");
}
public static void main(String args []) {
StaticTest st1 = new StaticTest();
st1.print();
StaticTest st2 = new StaticTest();
st2.print();
}
}
1) Never.
2) Each time a new instance is created.
3) Once when the class is first loaded into the Java virtual machine.
4) Only when the static method is called explicitly.
Answer : 3
What is the result of the following program:
public class Test {
public static void main (String args []) {
boolean a = false;
if (a = true)
System.out.println("Hello");
else
System.out.println("Goodbye");
}
}
1) Program produces no output but terminates correctly.
2) Program does not terminate.
3) Prints out "Hello"
4) Prints out "Goodbye"
Answer : 3
Examine the following code, it includes an inner class, what is the result:
public final class Test4 {
class Inner {
void test() {
if (Test4.this.flag); {
sample();
}
}
}
private boolean flag = true;
public void sample() {
System.out.println("Sample");
}
public Test4() {
(new Inner()).test();
}
public static void main(String args []) {
new Test4();
}
}
1) Prints out "Sample"
2) Program produces no output but terminates correctly.
3) Program does not terminate.
4) The program will not compile
Answer : 1
Carefully examine the following class:
public class Test5 {
public static void main (String args []) {
/* This is the start of a comment
if (true) {
Test5 = new test5();
System.out.println("Done the test");
}
/* This is another comment */
System.out.println ("The end");
}
}
1) Prints out "Done the test" and nothing else.
2) Program produces no output but terminates correctly.
3) Program does not terminate.
4) The program will not compile.
5) The program generates a runtime exception.
6) The program prints out "The end" and nothing else.
7) The program prints out "Done the test" and "The end"
Answer : 6
What is the result of compiling and running the following applet:
import java.applet.Applet;
import java.awt.*;
public class Sample extends Applet {
private String text = "Hello World";
public void init() {
add(new Label(text));
}
public Sample (String string) {
text = string;
}
}
It is accessed form the following HTML page:
<html>
<title>Sample Applet</title>
<body>
<applet code="Sample.class" width=200 height=200></applet>
</body>
</html>
1) Prints "Hello World".
2) Generates a runtime error.
3) Does nothing.
4) Generates a compile time error.
Answer : 2
What is the effect of compiling and (if possible) running this class:
public class Calc {
public static void main (String args []) {
int total = 0;
for (int i = 0, j = 10; total > 30; ++i, --j) {
System.out.println(" i = " + i + " : j = " + j);
total += (i + j);
}
System.out.println("Total " + total);
}
}
1) Produce a runtime error
2) Produce a compile time error
3) Print out "Total 0"
4) Generate the following as output:
i = 0 : j = 10
i = 1 : j = 9
i = 2 : j = 8
Total 30
Answer : 3
Utility Package
1) What is the Vector class?
ANSWER : The Vector class provides the capability to implement a growable array of objects.
2) What is the Set interface?
ANSWER : The Set interface provides methods for accessing the elements of a finite mathematical set.Sets do not allow duplicate elements.
3) What is Dictionary class?
ANSWER : The Dictionary class is the abstarct super class of Hashtable and Properties class.Dictionary provides the abstarct functions used to store and retrieve objects by key-value.This class allows any object to be used as a key or value.
4) What is the Hashtable class?
ANSWER : The Hashtable class implements a hash table data structure. A hash table indexes and stores objects in a dictionary using hash codes as the objects' keys. Hash codes are integer values that identify objects.
5) What is the Properties class?
Answer : The properties class is a subclass of Hashtable that can be read from or written to a stream.It also provides the capability to specify a set of default values to be used if a specified key is not found in the table. We have two methods load() and save().
6) What changes are needed to make the following prg to compile?
import java.util.*;
class Ques{
public static void main (String args[]) {
String s1 = "abc";
String s2 = "def";
Vector v = new Vector();
v.add(s1);
v.add(s2);
String s3 = v.elementAt(0) + v.elementAt(1);
System.out.println(s3);
}
}
ANSWER : Declare Ques as public B) Cast v.elementAt(0) to a String
C) Cast v.elementAt(1) to an Object. D) Import java.lang
ANSWER : B) Cast v.elementAt(0) to a String
8) What is the output of the prg.
import java.util.*;
class Ques{
public static void main (String args[]) {
String s1 = "abc";
String s2 = "def";
Stack stack = new Stack();
stack.push(s1);
stack.push(s2);
try{
String s3 = (String) stack.pop() + (String) stack.pop() ;
System.out.println(s3);
}catch (EmptyStackException ex){}
}
}
ANSWER : abcdef B) defabc C) abcabc D) defdef
ANSWER : B) defabc
9) Which of the following may have duplicate elements?
ANSWER : Collection B) List C) Map D) Set
ANSWER : A and B Neither a Map nor a Set may have duplicate elements.
10) Can null value be added to a List?
ANSWER : Yes.A Null value may be added to any List.
11) What is the output of the following prg.
import java.util.*;
class Ques{
public static void main (String args[]) {
HashSet set = new HashSet();
String s1 = "abc";
String s2 = "def";
String s3 = "";
set.add(s1);
set.add(s2);
set.add(s1);
set.add(s2);
Iterator i = set.iterator();
while(i.hasNext())
{
s3 += (String) i.next();
}
System.out.println(s3);
}
}
A) abcdefabcdef B) defabcdefabc C) fedcbafedcba D) defabc
ANSWER : D) defabc. Sets may not have duplicate elements.
12) Which of the following java.util classes support internationalization?
A) Locale B) ResourceBundle C) Country D) Language
ANSWER : A and B . Country and Language are not java.util classes.
13) What is the ResourceBundle?
The ResourceBundle class also supports internationalization.
ResourceBundle subclasses are used to store locale-specific resources that can be loaded by a program to tailor the program's appearence to the paticular locale in which it is being run. Resource Bundles provide the capability to isolate a program's locale-specific resources in a standard and modular manner.
14) How are Observer Interface and Observable class, in java.util package, used?
ANSWER : Objects that subclass the Observable class maintain a list of Observers. When an Observable object is updated it invokes the update() method of each of its observers to notify the observers that it has changed state. The Observer interface is implemented by objects that observe Observable objects.
15) Which java.util classes and interfaces support event handling?
ANSWER : The EventObject class and the EventListener interface support event processing.
16) Does java provide standard iterator functions for inspecting a collection of objects?
ANSWER : The Enumeration interface in the java.util package provides a framework for stepping once through a collection of objects. We have two methods in that interface.
public interface Enumeration {
boolean hasMoreElements();
Object nextElement();
}
17) The Math.random method is too limited for my needs- How can I generate random numbers more flexibly?
ANSWER : The random method in Math class provide quick, convienient access to random numbers, but more power and flexibility use the Random class in the java.util package.
double doubleval = Math.random();
The Random class provide methods returning float, int, double, and long values.
nextFloat() // type float; 0.0 <= value < 1.0
nextDouble() // type double; 0.0 <= value < 1.0
nextInt() // type int; Integer.MIN_VALUE <= value <= Integer.MAX_VALUE
nextLong() // type long; Long.MIN_VALUE <= value <= Long.MAX_VALUE
nextGaussian() // type double; has Gaussian("normal") distribution with mean 0.0 and standard deviation 1.0)
Eg. Random r = new Random();
float floatval = r.nextFloat();
18) How can we get all public methods of an object dynamically?
ANSWER : By using getMethods(). It return an array of method objects corresponding to the public methods of this class.
getFields() returns an array of Filed objects corresponding to the public Fields(variables) of this class.
getConstructors() returns an array of constructor objects corresponding to the public constructors of this class.
JDBC
1) What are the steps involved in establishing a connection?
ANSWER : This involves two steps: (1) loading the driver and (2) making the connection.
2) How can you load the drivers?
ANSWER : Loading the driver or drivers you want to use is very simple and involves just one line of code. If, for example, you want to use the JDBC-ODBC Bridge driver, the following code will load it:
Eg.
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
Your driver documentation will give you the class name to use. For instance, if the class name is jdbc.DriverXYZ , you would load the driver with the following line of code:
Eg.
Class.forName("jdbc.DriverXYZ");
3) What Class.forName will do while loading drivers?
ANSWER : It is used to create an instance of a driver and register it with the DriverManager.
When you have loaded a driver, it is available for making a connection with a DBMS.
4) How can you make the connection?
ANSWER : In establishing a connection is to have the appropriate driver connect to the DBMS. The following line of code illustrates the general idea:
Eg.
String url = "jdbc:odbc:Fred";
Connection con = DriverManager.getConnection(url, "Fernanda", "J8");
5) How can you create JDBC statements?
ANSWER : A Statement object is what sends your SQL statement to the DBMS. You simply create a Statement object and then execute it, supplying the appropriate execute method with the SQL statement you want to send. For a SELECT statement, the method to use is executeQuery. For statements that create or modify tables, the method to use is executeUpdate.
Eg.
It takes an instance of an active connection to create a Statement object. In the following example, we use our Connection object con to create the Statement object stmt :
Statement stmt = con.createStatement();
6) How can you retrieve data from the ResultSet?
ANSWER : Step 1.
JDBC returns results in a ResultSet object, so we need to declare an instance of the class ResultSet to hold our results. The following code demonstrates declaring the ResultSet object rs.
Eg.
ResultSet rs = stmt.executeQuery("SELECT COF_NAME, PRICE FROM COFFEES");
Step2.
String s = rs.getString("COF_NAME");
The method getString is invoked on the ResultSet object rs , so getString will retrieve (get) the value stored in the column COF_NAME in the current row of rs
7) What are the different types of Statements?
ANSWER : 1.Statement (use createStatement method) 2. Prepared Statement (Use prepareStatement method) and 3. Callable Statement (Use prepareCall)
8) How can you use PreparedStatement?
ANSWER : This special type of statement is derived from the more general class, Statement.If you want to execute a Statement object many times, it will normally reduce execution time to use a PreparedStatement object instead.
The advantage to this is that in most cases, this SQL statement will be sent to the DBMS right away, where it will be compiled. As a result, the PreparedStatement object contains not just an SQL statement, but an SQL statement that has been precompiled. This means that when the PreparedStatement is executed, the DBMS can just run the PreparedStatement 's SQL statement without having to compile it first.
Eg.
PreparedStatement updateSales = con.prepareStatement("UPDATE COFFEES SET SALES = ? WHERE COF_NAME LIKE ?");
9) What setAutoCommit does?
ANSWER : When a connection is created, it is in auto-commit mode. This means that each individual SQL statement is treated as a transaction and will be automatically committed right after it is executed. The way to allow two or more statements to be grouped into a transaction is to disable auto-commit mode
Eg.
con.setAutoCommit(false);
Once auto-commit mode is disabled, no SQL statements will be committed until you call the method commit explicitly.
Eg.
con.setAutoCommit(false);
PreparedStatement updateSales = con.prepareStatement(
"UPDATE COFFEES SET SALES = ? WHERE COF_NAME LIKE ?");
updateSales.setInt(1, 50);
updateSales.setString(2, "Colombian");
updateSales.executeUpdate();
PreparedStatement updateTotal = con.prepareStatement("UPDATE COFFEES SET TOTAL = TOTAL + ? WHERE COF_NAME LIKE ?");
updateTotal.setInt(1, 50);
updateTotal.setString(2, "Colombian");
updateTotal.executeUpdate();
con.commit();
con.setAutoCommit(true);
10) How to call a Strored Procedure from JDBC?
ANSWER : The first step is to create a CallableStatement object. As with Statement an and PreparedStatement objects, this is done with an open Connection
object. A CallableStatement object contains a call to a stored procedure;
Eg.
CallableStatement cs = con.prepareCall("{call SHOW_SUPPLIERS}");
ResultSet rs = cs.executeQuery();
11) How to Retrieve Warnings?
ANSWER : SQLWarning objects are a subclass of SQLException that deal with database access warnings. Warnings do not stop the execution of an application, as exceptions do; they simply alert the user that something did not happen as planned.
A warning can be reported on a Connection object, a Statement object (including PreparedStatement and CallableStatement objects), or a ResultSet object. Each of these classes has a getWarnings method, which you must invoke in order to see the first warning reported on the calling object
Eg.
SQLWarning warning = stmt.getWarnings();
if (warning != null) {
System.out.println("\n---Warning---\n");
while (warning != null) {
System.out.println("Message: " + warning.getMessage());
System.out.println("SQLState: " + warning.getSQLState());
System.out.print("Vendor error code: ");
System.out.println(warning.getErrorCode());
System.out.println("");
warning = warning.getNextWarning();
}
}
12) How can you Move the Cursor in Scrollable Result Sets ?
ANSWER : One of the new features in the JDBC 2.0 API is the ability to move a result set's cursor backward as well as forward. There are also methods that let you move the cursor to a particular row and check the position of the cursor.
Eg.
Statement stmt = con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,
ResultSet.CONCUR_READ_ONLY);
ResultSet srs = stmt.executeQuery("SELECT COF_NAME, PRICE FROM COFFEES");
The first argument is one of three constants added to the ResultSet API to indicate the type of a ResultSet object: TYPE_FORWARD_ONLY, TYPE_SCROLL_INSENSITIVE , and TYPE_SCROLL_SENSITIVE .
The second argument is one of two ResultSet constants for specifying whether a result set is read-only or updatable: CONCUR_READ_ONLY and CONCUR_UPDATABLE . The point to remember here is that if you specify a type, you must also specify whether it is read-only or updatable. Also, you must specify the type first, and because both parameters are of type int , the compiler will not complain if you switch the order.
Specifying the constant TYPE_FORWARD_ONLY creates a nonscrollable result set, that is, one in which the cursor moves only forward. If you do not specify any constants for the type and updatability of a ResultSet object, you will automatically get one that is TYPE_FORWARD_ONLY and CONCUR_READ_ONLY
13) What’s the difference between TYPE_SCROLL_INSENSITIVE , and TYPE_SCROLL_SENSITIVE?
ANSWER : You will get a scrollable ResultSet object if you specify one of these ResultSet constants.The difference between the two has to do with whether a result set reflects changes that are made to it while it is open and whether certain methods can be called to detect these changes. Generally speaking, a result set that is TYPE_SCROLL_INSENSITIVE does not reflect changes made while it is still open and one that is TYPE_SCROLL_SENSITIVE does. All three types of result sets will make changes visible if they are closed and then reopened
Eg.
Statement stmt = con.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_READ_ONLY);
ResultSet srs = stmt.executeQuery("SELECT COF_NAME, PRICE FROM COFFEES");
srs.afterLast();
while (srs.previous()) {
String name = srs.getString("COF_NAME");
float price = srs.getFloat("PRICE");
System.out.println(name + " " + price);
}
14) How to Make Updates to Updatable Result Sets?
ANSWER : Another new feature in the JDBC 2.0 API is the ability to update rows in a result set using methods in the Java programming language rather than having to send an SQL command. But before you can take advantage of this capability, you need to create a ResultSet object that is updatable. In order to do this, you supply the ResultSet constant CONCUR_UPDATABLE to the createStatement method.
Eg.
Connection con = DriverManager.getConnection("jdbc:mySubprotocol:mySubName");
Statement stmt = con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,
ResultSet.CONCUR_UPDATABLE);
ResultSet uprs = stmt.executeQuery("SELECT COF_NAME, PRICE FROM COFFEES");
Networking Concepts
1) The API doesn't list any constructors for InetAddress- How do I create an InetAddress instance?
ANSWER : In case of InetAddress the three methods getLocalHost, getByName, getByAllName can be used to create instances.
E.g.
InetAddress add1;
InetAddress add2;
try{
add1 = InetAddress.getByName("java.sun.com");
add2 = InetAddress.getByName("199.22.22.22");
}catch(UnknownHostException e){}
2) Is it possible to get the Local host IP?
ANSWER : Yes. Use InetAddress's getLocalHost method.
3) What's the Factory Method?
ANSWER : Factory methods are merely a convention whereby static methods in a class return an instance of that class. The InetAddress class has no visible constructors. To create an InetAddress object, you have to use one of the available factory methods. In InetAddress the three methods getLocalHost, getByName, getByAllName can be used to create instances of InetAddress.
4) What’s the difference between TCP and UDP?
ANSWER : These two protocols differ in the way they carry out the action of communicating. A TCP protocol establishes a two way connection between a pair of computers, while the UDP protocol is a one-way message sender. The common analogy is that TCP is like making a phone call and carrying on a two-way communication, while UDP is like mailing a letter.
5) What is the Proxy Server?
ANSWER : A proxy server speaks the client side of a protocol to another server. This is often required when clients have certain restrictions on which servers they can connect to. And when several users are hitting a popular web site, a proxy server can get the contents of the web server's popular pages once, saving expensive internetwork transfers while providing faster access to those pages to the clients.
Also, we can get multiple connections for a single server.
6) What are the seven layers of OSI model?
ANSWER : Application, Presentation, Session, Transport, Network, DataLink, Physical Layer.
What Transport Layer does?
ANSWER : It ensures that the mail gets to its destination. If a packet fails to get its destination, it handles the process of notifying the sender and requesting that another packet be sent.
8) What is DHCP?
ANSWER : Dynamic Host Configuration Protocol, a piece of the TCP/IP protocol suite that handles the automatic assignment of IP addresses to clients.
9) What is SMTP?
ANSWER : Simple Mail Transmission Protocol, the TCP/IP Standard for Internet mails. SMTP exchanges mail between servers; contrast this with POP, which transmits mail between a server and a client.
10) In OSI N/w architecture, the dialogue control and token management are responsibilities of...
Answer : Network b) Session c) Application d) DataLink
ANSWER : b) Session Layer.
11) In OSI N/W Architecture, the routing is performed by ______
Answer : Network b) Session c) Application d) DataLink
ANSWER : Answer : Network Layer.
Networking
What is the difference between URL instance and URLConnection instance?
ANSWER : A URL instance represents the location of a resource, and a URLConnection instance represents a link for accessing or communicating with the resource at the location.
2) How do I make a connection to URL?
ANSWER : You obtain a URL instance and then invoke openConnection on it.
URLConnection is an abstract class, which means you can't directly create instances of it using a constructor. We have to invoke openConnection method on a URL instance, to get the right kind of connection for your URL.
Eg. URL url;
URLConnection connection;
try{ url = new URL("...");
conection = url.openConnection();
}catch (MalFormedURLException e) { }
3) What Is a Socket?
A socket is one end-point of a two-way communication link between two programs running on the network. A socket is bound to a port number so that the TCP layer can identify the application that data is destined to be sent.Socket classes are used to represent the connection between a client program and a server program. The java.net package provides two classes--Socket and ServerSocket--which implement the client side of the connection and the server side of the connection, respectively.
What information is needed to create a TCP Socket?
ANSWER : The Local System’s IP Address and Port Number.
And the Remote System's IPAddress and Port Number.
5) What are the two important TCP Socket classes?
ANSWER : Socket and ServerSocket.
ServerSocket is used for normal two-way socket communication. Socket class allows us to read and write through the sockets.
getInputStream() and getOutputStream() are the two methods available in Socket class.
When MalformedURLException and UnknownHostException throws?
ANSWER : When the specified URL is not connected then the URL throw MalformedURLException and If InetAddress’ methods getByName and getLocalHost are unabletoresolve the host name they throwan UnknownHostException.
Servlets
1) What is the servlet?
ANSWER : Servlets are modules that extend request/response-oriented servers, such as Java-enabled web servers. For example, a servlet might be responsible for taking data in an HTML order-entry form and applying the business logic used to update a company's order database.
Servlets are to servers what applets are to browsers. Unlike applets, however, servlets have no graphical user interface.
2) Whats the advantages using servlets than using CGI?
ANSWER : Servlets provide a way to generate dynamic documents that is both easier to write and faster to run. Servlets also address the problem of doing server-side programming with platform-specific APIs: they are developed with the Java Servlet API, a standard Java extension.
3) What are the uses of Servlets?
ANSWER : A servlet can handle multiple requests concurrently, and can synchronize requests. This allows servlets to support systems such as on-line conferencing.
Servlets can forward requests to other servers and servlets.Thus servlets can be used to balance load among several servers that mirror the same content, and to partition a single logical service over several servers, according to task type or organizational boundaries.
4) Which pakage provides interfaces and classes for writing servlets?
ANSWER : javax
5) Whats the Servlet Interfcae?
ANSWER : The central abstraction in the Servlet API is the Servlet interface. All servlets implement this interface, either directly or, more commonly, by extending a class that implements it such as HttpServlet.
Servlets-->Generic Servlet-->HttpServlet-->MyServlet.
The Servlet interface declares, but does not implement, methods that manage the servlet and its communications with clients. Servlet writers provide some or all of these methods when developing a servlet.
6) When a servlet accepts a call from a client, it receives two objects- What are they?
ANSWER : ServeltRequest: Which encapsulates the communication from the client to the server.
ServletResponse: Whcih encapsulates the communication from the servlet back to the client.
ServletRequest and ServletResponse are interfaces defined by the javax.servlet package.
7) What information that the ServletRequest interface allows the servlet access to?
ANSWER : Information such as the names of the parameters passed in by the client, the protocol (scheme) being used by the client, and the names of the remote host that made the request and the server that received it.
The input stream, ServletInputStream.Servlets use the input stream to get data from clients that use application protocols such as the HTTP POST and PUT methods.
8) What information that the ServletResponse interface gives the servlet methods for replying to the client?
ANSWER : It Allows the servlet to set the content length and MIME type of the reply.
Provides an output stream, ServletOutputStream and a Writer through which the servlet can send the reply data.
9) What is the servlet Lifecycle?
ANSWER : Each servlet has the same life cycle:
A server loads and initializes the servlet (init())
The servlet handles zero or more client requests (service())
The server removes the servlet (destroy())
(some servers do this step only when they shut down)
10) How HTTP Servlet handles client requests?
ANSWER : An HTTP Servlet handles client requests through its service method. The service method supports standard HTTP client requests by dispatching each request to a method designed to handle that request. 1
Encapsulation :
Encapsulation is the mechanism that binds together code and the data it manipulates and keeps both safe from outside interference and misuse.
Inheritance:
Inheritance is the process by which one object acquires the properties of another object.
Polymorphism:
Polymorphism is a feature that allows one interface to be used for a general class of actions. The specific action is determined by the exact nature of actions.
Code Blocks:
Two or more statements which is allowed to be grouped into blocks of code is otherwise called as Code Blocks.This is done by enclosing the statements between opening and closing curly braces.
Floating-point numbers:
Floating-point numbers which is also known as real numbers, are used when evaluating expressions that require fractional precision.
Unicode:
Unicode defines a fully international character set that can represent all of the characters found in all human languages. It is a unification of dozens of character sets, such as Latin, Greek, Arabic and many more.
Booleans:
Java has a simple type called boolean, for logical values. It can have only on of two possible values, true or false.
Casting:
A cast is simply an explicit type conversion. To create a conversion between two incompatible types, you must use a cast.
Arrays:
An array is a group of like-typed variables that are referred to by a common name. Arrays offer a convenient means of grouping related information. Arrays of any type can be created and may have one or more dimension.
Relational Operators:
The relational operators determine the relationship that one operand has to the other. They determine the equality and ordering.
11.Short-Circuit Logical Operators:
The secondary versions of the Boolean AND and OR operators are known as short-
circuit logical operators. It is represented by || and &&..
12. Switch:
The switch statement is Java’s multiway branch statement. It provides an easy way to
dispatch execution to different parts of your code based on the value of an
experession.
13. Jump Statements:
Jump statements are the statements which transfer control to another part of your
program. Java Supports three jump statements: break, continue, and return.
14. Instance Variables:
The data, or variable, defined within a class are called instance variable.
C++ Questions
Note : All the programs are tested under Turbo C++ 3.0, 4.5 and Microsoft VC++ 6.0 compilers.
It is assumed that,
Programs run under Windows environment,
The underlying machine is an x86 based system,
Program is compiled using Turbo C/C++ compiler.
The program output may depend on the information based on this assumptions (for example sizeof(int) == 2 may be assumed).
1) class Sample
{
public:
int *ptr;
Sample(int i)
{
ptr = new int(i);
}
~Sample()
{
delete ptr;
}
void PrintVal()
{
cout << "The value is " << *ptr;
}
};
void SomeFunc(Sample x)
{
cout << "Say i am in someFunc " << endl;
}
int main()
{
Sample s1= 10;
SomeFunc(s1);
s1.PrintVal();
}
Answer:
Say i am in someFunc
Null pointer assignment(Run-time error)
Explanation:
As the object is passed by value to SomeFunc the destructor of the object is called when the control returns from the function. So when PrintVal is called it meets up with ptr that has been freed.The solution is to pass the Sample object by reference to SomeFunc:
void SomeFunc(Sample &x)
{
cout << "Say i am in someFunc " << endl;
}
because when we pass objects by refernece that object is not destroyed. while returning from the function.
2) Which is the parameter that is added to every non-static member function when it is called?
Answer:
‘this’ pointer
3) class base
{
public:
int bval;
base(){ bval=0;}
};
class deri:public base
{
public:
int dval;
deri(){ dval=1;}
};
void SomeFunc(base *arr,int size)
{
for(int i=0; i<size; i++,arr++)
cout<<arr->bval;
cout<<endl;
}
int main()
{
base BaseArr[5];
SomeFunc(BaseArr,5);
deri DeriArr[5];
SomeFunc(DeriArr,5);
}
Answer:
00000
01010
Explanation:
The function SomeFunc expects two arguments.The first one is a pointer to an array of base class objects and the second one is the sizeof the array.The first call of someFunc calls it with an array of bae objects, so it works correctly and prints the bval of all the objects. When Somefunc is called the second time the argument passed is the pointeer to an array of derived class objects and not the array of base class objects. But that is what the function expects to be sent. So the derived class pointer is promoted to base class pointer and the address is sent to the function. SomeFunc() knows nothing about this and just treats the pointer as an array of base class objects. So when arr++ is met, the size of base class object is taken into consideration and is incremented by sizeof(int) bytes for bval (the deri class objects have bval and dval as members and so is of size >= sizeof(int)+sizeof(int) ).
4) class base
{
public:
void baseFun(){ cout<<"from base"<<endl;}
};
class deri:public base
{
public:
void baseFun(){ cout<< "from derived"<<endl;}
};
void SomeFunc(base *baseObj)
{
baseObj->baseFun();
}
int main()
{
base baseObject;
SomeFunc(&baseObject);
deri deriObject;
SomeFunc(&deriObject);
}
Answer:
from base
from base
Explanation:
As we have seen in the previous case, SomeFunc expects a pointer to a base class. Since a pointer to a derived class object is passed, it treats the argument only as a base class pointer and the corresponding base function is called.
5) class base
{
public:
virtual void baseFun(){ cout<<"from base"<<endl;}
};
class deri:public base
{
public:
void baseFun(){ cout<< "from derived"<<endl;}
};
void SomeFunc(base *baseObj)
{
baseObj->baseFun();
}
int main()
{
base baseObject;
SomeFunc(&baseObject);
deri deriObject;
SomeFunc(&deriObject);
}
Answer:
from base
from derived
Explanation:
Remember that baseFunc is a virtual function. That means that it supports run-time polymorphism. So the function corresponding to the derived class object is called.
void main()
{
int a, *pa, &ra;
pa = &a;
ra = a;
cout <<"a="<<a <<"*pa="<<*pa <<"ra"<<ra ;
}
/*
Answer :
Compiler Error: 'ra',reference must be initialized
Explanation :
Pointers are different from references. One of the main
differences is that the pointers can be both initialized and assigned,
whereas references can only be initialized. So this code issues an error.
*/
const int size = 5;
void print(int *ptr)
{
cout<<ptr[0];
}
void print(int ptr[size])
{
cout<<ptr[0];
}
void main()
{
int a[size] = {1,2,3,4,5};
int *b = new int(size);
print(a);
print(b);
}
/*
Answer:
Compiler Error : function 'void print(int *)' already has a body
Explanation:
Arrays cannot be passed to functions, only pointers (for arrays, base addresses)
can be passed. So the arguments int *ptr and int prt[size] have no difference
as function arguments. In other words, both the functoins have the same signature and
so cannot be overloaded.
*/
class some{
public:
~some()
{
cout<<"some's destructor"<<endl;
}
};
void main()
{
some s;
s.~some();
}
/*
Answer:
some's destructor
some's destructor
Explanation:
Destructors can be called explicitly. Here 's.~some()' explicitly calls the
destructor of 's'. When main() returns, destructor of s is called again,
hence the result.
*/
#include <iostream.h>
class fig2d
{
int dim1;
int dim2;
public:
fig2d() { dim1=5; dim2=6;}
virtual void operator<<(ostream & rhs);
};
void fig2d::operator<<(ostream &rhs)
{
rhs <<this->dim1<<" "<<this->dim2<<" ";
}
/*class fig3d : public fig2d
{
int dim3;
public:
fig3d() { dim3=7;}
virtual void operator<<(ostream &rhs);
};
void fig3d::operator<<(ostream &rhs)
{
fig2d::operator <<(rhs);
rhs<<this->dim3;
}
*/
void main()
{
fig2d obj1;
// fig3d obj2;
obj1 << cout;
// obj2 << cout;
}
/*
Answer :
5 6
Explanation:
In this program, the << operator is overloaded with ostream as argument.
This enables the 'cout' to be present at the right-hand-side. Normally, 'cout'
is implemented as global function, but it doesn't mean that 'cout' is not possible
to be overloaded as member function.
Overloading << as virtual member function becomes handy when the class in which
it is overloaded is inherited, and this becomes available to be overrided. This is as opposed
to global friend functions, where friend's are not inherited.
*/
class opOverload{
public:
bool operator==(opOverload temp);
};
bool opOverload::operator==(opOverload temp){
if(*this == temp ){
cout<<"The both are same objects\n";
return true;
}
else{
cout<<"The both are different\n";
return false;
}
}
void main(){
opOverload a1, a2;
a1= =a2;
}
Answer :
Runtime Error: Stack Overflow
Explanation :
Just like normal functions, operator functions can be called recursively. This program just illustrates that point, by calling the operator == function recursively, leading to an infinite loop.
class complex{
double re;
double im;
public:
complex() : re(1),im(0.5) {}
bool operator==(complex &rhs);
operator int(){}
};
bool complex::operator == (complex &rhs){
if((this->re == rhs.re) && (this->im == rhs.im))
return true;
else
return false;
}
int main(){
complex c1;
cout<< c1;
}
Answer : Garbage value
Explanation:
The programmer wishes to print the complex object using output
re-direction operator,which he has not defined for his lass.But the compiler instead of giving an error sees the conversion function
and converts the user defined object to standard object and prints
some garbage value.
class complex{
double re;
double im;
public:
complex() : re(0),im(0) {}
complex(double n) { re=n,im=n;};
complex(int m,int n) { re=m,im=n;}
void print() { cout<<re; cout<<im;}
};
void main(){
complex c3;
double i=5;
c3 = i;
c3.print();
}
Answer:
5,5
Explanation:
Though no operator= function taking complex, double is defined, the double on the rhs is converted into a temporary object using the single argument constructor taking double and assigned to the lvalue.
void main()
{
int a, *pa, &ra;
pa = &a;
ra = a;
cout <<"a="<<a <<"*pa="<<*pa <<"ra"<<ra ;
}
Answer :
Compiler Error: 'ra',reference must be initialized
Explanation :
Pointers are different from references. One of the main
differences is that the pointers can be both initialized and assigned,
whereas references can only be initialized. So this code issues an error.
Try it Yourself
1) Determine the output of the 'C++' Codelet.
class base
{
public :
out()
{
cout<<"base ";
}
};
class deri{
public : out()
{
cout<<"deri ";
}
};
void main()
{ deri dp[3];
base *bp = (base*)dp;
for (int i=0; i<3;i++)
(bp++)->out();
}
2) Justify the use of virtual constructors and destructors in C++.
3) Each C++ object possesses the 4 member fns,(which can be declared by the programmer explicitly or by the implementation if they are not available). What are those 4 functions?
4) What is wrong with this class declaration?
class something
{
char *str;
public:
something(){
st = new char[10]; }
~something()
{
delete str;
}
};
5) Inheritance is also known as -------- relationship. Containership as ________ relationship.
6) When is it necessary to use member-wise initialization list (also known as header initialization list) in C++?
7) Which is the only operator in C++ which can be overloaded but NOT inherited.
8) Is there anything wrong with this C++ class declaration?
class temp
{
int value1;
mutable int value2;
public :
void fun(int val)
const{
((temp*) this)->value1 = 10;
value2 = 10;
}
};
1. What is a modifier?
Answer:
A modifier, also called a modifying function is a member function that changes the value of at least one data member. In other words, an operation that modifies the state of an object. Modifiers are also known as ‘mutators’.
2. What is an accessor?
Answer:
An accessor is a class operation that does not modify the state of an object. The accessor functions need to be declared as const operations
3. Differentiate between a template class and class template.
Answer:
Template class:
A generic definition or a parameterized class not instantiated until the client provides the needed information. It’s jargon for plain templates.
Class template:
A class template specifies how individual classes can be constructed much like the way a class specifies how individual objects can be constructed. It’s jargon for plain classes.
4. When does a name clash occur?
Answer:
A name clash occurs when a name is defined in more than one place. For example., two different class libraries could give two different classes the same name. If you try to use many class libraries at the same time, there is a fair chance that you will be unable to compile or link the program because of name clashes.
5. Define namespace.
Answer:
It is a feature in c++ to minimize name collisions in the global name space. This namespace keyword assigns a distinct name to a library that allows other libraries to use the same identifier names without creating any name collisions. Furthermore, the compiler uses the namespace signature for differentiating the definitions.
6. What is the use of ‘using’ declaration.
Answer:
A using declaration makes it possible to use a name from a namespace without the scope operator.
7. What is an Iterator class?
Answer:
A class that is used to traverse through the objects maintained by a container class. There are five categories of iterators:
. input iterators,
. output iterators,
. forward iterators,
. bidirectional iterators,
. random access.
An iterator is an entity that gives access to the contents of a container object without violating encapsulation constraints. Access to the contents is granted on a one-at-a-time basis in order. The order can be storage order (as in lists and queues) or some arbitrary order (as in array indices) or according to some ordering relation (as in an ordered binary tree). The iterator is a construct, which provides an interface that, when called, yields either the next element in the container, or some value denoting the fact that there are no more elements to examine. Iterators hide the details of access to and update of the elements of a container class.
The simplest and safest iterators are those that permit read-only access to the contents of a container class. The following code fragment shows how an iterator might appear in code:
cont_iter:=new cont_iterator();
x:=cont_iter.next();
while x/=none do
...
s(x);
...
x:=cont_iter.next();
end;
In this example, cont_iter is the name of the iterator. It is created on the first line by instantiation of cont_iterator class, an iterator class defined to iterate over some container class, cont. Succesive elements from the container are carried to x. The loop terminates when x is bound to some empty value. (Here, none)In the middle of the loop, there is s(x) an operation on x, the current element from the container. The next element of the container is obtained at the bottom of the loop.
9. List out some of the OODBMS available.
Answer:
. GEMSTONE/OPAL of Gemstone systems.
. ONTOS of Ontos.
. Objectivity of Objectivity inc.
. Versant of Versant object technology.
. Object store of Object Design.
. ARDENT of ARDENT software.
. POET of POET software.
10. List out some of the object-oriented methodologies.
Answer:
. Object Oriented Development (OOD) (Booch 1991,1994).
. Object Oriented Analysis and Design (OOA/D) (Coad and Yourdon 1991).
. Object Modelling Techniques (OMT) (Rumbaugh 1991).
. Object Oriented Software Engineering (Objectory) (Jacobson 1992).
. Object Oriented Analysis (OOA) (Shlaer and Mellor 1992).
. The Fusion Method (Coleman 1991).
11. What is an incomplete type?
Answer:
Incomplete types refers to pointers in which there is non availability of the implementation of the referenced location or it points to some location whose value is not available for modification.
Example:
int *i=0x400 // i points to address 400
*i=0; //set the value of memory location pointed by i.
Incomplete types are otherwise called uninitialized pointers.
12. What is a dangling pointer?
Answer:
A dangling pointer arises when you use the address of an object after its lifetime is over.
This may occur in situations like returning addresses of the automatic variables from a function or using the address of the memory block after it is freed.
13. Differentiate between the message and method.
Answer:
Message Method
Objects communicate by sending messages Provides response to a message.
to each other.
A message is sent to invoke a method. It is an implementation of an operation.
14. What is an adaptor class or Wrapper class?
Answer:
A class that has no functionality of its own. Its member functions hide the use of a third party software component or an object with the non-compatible interface or a non- object- oriented implementation.
15. What is a Null object?
Answer:
It is an object of some class whose purpose is to indicate that a real object of that class does not exist. One common use for a null object is a return value from a member function that is supposed to return an object with some specified properties but cannot find such an object.
16. What is class invariant?
Answer:
A class invariant is a condition that defines all valid states for an object. It is a logical condition to ensure the correct working of a class. Class invariants must hold when an object is created, and they must be preserved under all operations of the class. In particular all class invariants are both preconditions and post-conditions for all operations or member functions of the class.
17. What do you mean by Stack unwinding?
Answer:
It is a process during exception handling when the destructor is called for all local objects between the place where the exception was thrown and where it is caught.
18. Define precondition and post-condition to a member function.
Answer:
Precondition:
A precondition is a condition that must be true on entry to a member function. A class is used correctly if preconditions are never false. An operation is not responsible for doing anything sensible if its precondition fails to hold.
For example, the interface invariants of stack class say nothing about pushing yet another element on a stack that is already full. We say that isful() is a precondition of the push operation.
Post-condition:
A post-condition is a condition that must be true on exit from a member function if the precondition was valid on entry to that function. A class is implemented correctly if post-conditions are never false.
For example, after pushing an element on the stack, we know that isempty() must necessarily hold. This is a post-condition of the push operation.
19. What are the conditions that have to be met for a condition to be an invariant of the class?
Answer:
. The condition should hold at the end of every constructor.
. The condition should hold at the end of every mutator(non-const) operation.
20. What are proxy objects?
Answer:
Objects that stand for other objects are called proxy objects or surrogates.
Example:
template<class T>
class Array2D
{
public:
class Array1D
{
public:
T& operator[] (int index);
const T& operator[] (int index) const;
...
};
Array1D operator[] (int index);
const Array1D operator[] (int index) const;
...
};
The following then becomes legal:
Array2D<float>data(10,20);
........
cout<<data[3][6]; // fine
Here data[3] yields an Array1D object and the operator [] invocation on that object yields the float in position(3,6) of the original two dimensional array. Clients of the Array2D class need not be aware of the presence of the Array1D class. Objects of this latter class stand for one-dimensional array objects that, conceptually, do not exist for clients of Array2D. Such clients program as if they were using real, live, two-dimensional arrays. Each Array1D object stands for a one-dimensional array that is absent from a conceptual model used by the clients of Array2D. In the above example, Array1D is a proxy class. Its instances stand for one-dimensional arrays that, conceptually, do not exist.
21. Name some pure object oriented languages.
Answer:
. Smalltalk,
. Java,
. Eiffel,
. Sather.
22. Name the operators that cannot be overloaded.
Answer:
sizeof . .* .-> :: ?:
23. What is a node class?
Answer:
A node class is a class that,
. relies on the base class for services and implementation,
. provides a wider interface to te users than its base class,
. relies primarily on virtual functions in its public interface
. depends on all its direct and indirect base class
. can be understood only in the context of the base class
. can be used as base for further derivation
. can be used to create objects.
A node class is a class that has added new services or functionality beyond the services inherited from its base class.
24. What is an orthogonal base class?
Answer:
If two base classes have no overlapping methods or data they are said to be independent of, or orthogonal to each other. Orthogonal in the sense means that two classes operate in different dimensions and do not interfere with each other in any way. The same derived class may inherit such classes with no difficulty.
25. What is a container class? What are the types of container classes?
Answer:
A container class is a class that is used to hold objects in memory or external storage. A container class acts as a generic holder. A container class has a predefined behavior and a well-known interface. A container class is a supporting class whose purpose is to hide the topology used for maintaining the list of objects in memory. When a container class contains a group of mixed objects, the container is called a heterogeneous container; when the container is holding a group of objects that are all the same, the container is called a homogeneous container.
26. What is a protocol class?
Answer:
An abstract class is a protocol class if:
. it neither contains nor inherits from classes that contain member data, non-virtual functions, or private (or protected) members of any kind.
. it has a non-inline virtual destructor defined with an empty implementation,
. all member functions other than the destructor including inherited functions, are declared pure virtual functions and left undefined.
27. What is a mixin class?
Answer:
A class that provides some but not all of the implementation for a virtual base class is often called mixin. Derivation done just for the purpose of redefining the virtual functions in the base classes is often called mixin inheritance. Mixin classes typically don't share common bases.
28. What is a concrete class?
Answer:
A concrete class is used to define a useful object that can be instantiated as an automatic variable on the program stack. The implementation of a concrete class is defined. The concrete class is not intended to be a base class and no attempt to minimize dependency on other classes in the implementation or behavior of the class.
29.What is the handle class?
Answer:
A handle is a class that maintains a pointer to an object that is programmatically accessible through the public interface of the handle class.
Explanation:
In case of abstract classes, unless one manipulates the objects of these classes through pointers and references, the benefits of the virtual functions are lost. User code may become dependent on details of implementation classes because an abstract type cannot be allocated statistically or on the stack without its size being known. Using pointers or references implies that the burden of memory management falls on the user. Another limitation of abstract class object is of fixed size. Classes however are used to represent concepts that require varying amounts of storage to implement them.
A popular technique for dealing with these issues is to separate what is used as a single object in two parts: a handle providing the user interface and a representation holding all or most of the object's state. The connection between the handle and the representation is typically a pointer in the handle. Often, handles have a bit more data than the simple representation pointer, but not much more. Hence the layout of the handle is typically stable, even when the representation changes and also that handles are small enough to move around relatively freely so that the user needn’t use the pointers and the references.
30. What is an action class?
Answer:
The simplest and most obvious way to specify an action in C++ is to write a function. However, if the action has to be delayed, has to be transmitted 'elsewhere' before being performed, requires its own data, has to be combined with other actions, etc then it often becomes attractive to provide the action in the form of a class that can execute the desired action and provide other services as well. Manipulators used with iostreams is an obvious example.
Explanation:
A common form of action class is a simple class containing just one virtual function.
class Action
{
public:
virtual int do_it( int )=0;
virtual ~Action( );
}
Given this, we can write code say a member that can store actions for later execution without using pointers to functions, without knowing anything about the objects involved, and without even knowing the name of the operation it invokes. For example:
class write_file : public Action
{
File& f;
public:
int do_it(int)
{
return fwrite( ).suceed( );
}
};
class error_message: public Action
{
response_box db(message.cstr( ),"Continue","Cancel","Retry");
switch (db.getresponse( ))
{
case 0: return 0;
case 1: abort();
case 2: current_operation.redo( );return 1;
}
};
A user of the Action class will be completely isolated from any knowledge of derived classes such as write_file and error_message.
31. When can you tell that a memory leak will occur?
Answer:
A memory leak occurs when a program loses the ability to free a block of dynamically allocated memory.
32.What is a parameterized type?
Answer:
A template is a parameterized construct or type containing generic code that can use or manipulate any type. It is called parameterized because an actual type is a parameter of the code body. Polymorphism may be achieved through parameterized types. This type of polymorphism is called parameteric polymorphism. Parameteric polymorphism is the mechanism by which the same code is used on different types passed as parameters.
33. Differentiate between a deep copy and a shallow copy?
Answer:
Deep copy involves using the contents of one object to create another instance of the same class. In a deep copy, the two objects may contain ht same information but the target object will have its own buffers and resources. the destruction of either object will not affect the remaining object. The overloaded assignment operator would create a deep copy of objects.
Shallow copy involves copying the contents of one object into another instance of the same class thus creating a mirror image. Owing to straight copying of references and pointers, the two objects will share the same externally contained contents of the other object to be unpredictable.
Explanation:
Using a copy constructor we simply copy the data values member by member. This method of copying is called shallow copy. If the object is a simple class, comprised of built in types and no pointers this would be acceptable. This function would use the values and the objects and its behavior would not be altered with a shallow copy, only the addresses of pointers that are members are copied and not the value the address is pointing to. The data values of the object would then be inadvertently altered by the function. When the function goes out of scope, the copy of the object with all its data is popped off the stack.
If the object has any pointers a deep copy needs to be executed. With the deep copy of an object, memory is allocated for the object in free store and the elements pointed to are copied. A deep copy is used for objects that are returned from a function.
34. What is an opaque pointer?
Answer:
A pointer is said to be opaque if the definition of the type to which it points to is not included in the current translation unit. A translation unit is the result of merging an implementation file with all its headers and header files.
35. What is a smart pointer?
Answer:
A smart pointer is an object that acts, looks and feels like a normal pointer but offers more functionality. In C++, smart pointers are implemented as template classes that encapsulate a pointer and override standard pointer operators. They have a number of advantages over regular pointers. They are guaranteed to be initialized as either null pointers or pointers to a heap object. Indirection through a null pointer is checked. No delete is ever necessary. Objects are automatically freed when the last pointer to them has gone away. One significant problem with these smart pointers is that unlike regular pointers, they don't respect inheritance. Smart pointers are unattractive for polymorphic code. Given below is an example for the implementation of smart pointers.
Example:
template <class X>
class smart_pointer
{
public:
smart_pointer(); // makes a null pointer
smart_pointer(const X& x) // makes pointer to copy of x
X& operator *( );
const X& operator*( ) const;
X* operator->() const;
smart_pointer(const smart_pointer <X> &);
const smart_pointer <X> & operator =(const smart_pointer<X>&);
~smart_pointer();
private:
//...
};
This class implement a smart pointer to an object of type X. The object itself is located on the heap. Here is how to use it:
smart_pointer <employee> p= employee("Harris",1333);
Like other overloaded operators, p will behave like a regular pointer,
cout<<*p;
p->raise_salary(0.5);
36. What is reflexive association?
Answer:
The 'is-a' is called a reflexive association because the reflexive association permits classes to bear the is-a association not only with their super-classes but also with themselves. It differs from a 'specializes-from' as 'specializes-from' is usually used to describe the association between a super-class and a sub-class. For example:
Printer is-a printer.
37. What is slicing?
Answer:
Slicing means that the data added by a subclass are discarded when an object of the subclass is passed or returned by value or from a function expecting a base class object.
Explanation:
Consider the following class declaration:
class base
{
...
base& operator =(const base&);
base (const base&);
}
void fun( )
{
base e=m;
e=m;
}
As base copy functions don't know anything about the derived only the base part of the derived is copied. This is commonly referred to as slicing. One reason to pass objects of classes in a hierarchy is to avoid slicing. Other reasons are to preserve polymorphic behavior and to gain efficiency.
38. What is name mangling?
Answer:
Name mangling is the process through which your c++ compilers give each function in your program a unique name. In C++, all programs have at-least a few functions with the same name. Name mangling is a concession to the fact that linker always insists on all function names being unique.
Example:
In general, member names are made unique by concatenating the name of the member with that of the class e.g. given the declaration:
class Bar
{
public:
int ival;
...
};
ival becomes something like:
// a possible member name mangling
ival__3Bar
Consider this derivation:
class Foo : public Bar
{
public:
int ival;
...
}
The internal representation of a Foo object is the concatenation of its base and derived class members.
// Pseudo C++ code
// Internal representation of Foo
class Foo
{
public:
int ival__3Bar;
int ival__3Foo;
...
};
Unambiguous access of either ival members is achieved through name mangling. Member functions, because they can be overloaded, require an extensive mangling to provide each with a unique name. Here the compiler generates the same name for the two overloaded instances(Their argument lists make their instances unique).
39. What are proxy objects?
Answer:
Objects that points to other objects are called proxy objects or surrogates. Its an object that provides the same interface as its server object but does not have any functionality. During a method invocation, it routes data to the true server object and
40. Differentiate between declaration and definition in C++.
Answer:
A declaration introduces a name into the program; a definition provides a unique description of an entity (e.g. type, instance, and function). Declarations can be repeated in a given scope, it introduces a name in a given scope. There must be exactly one definition of every object, function or class used in a C++ program.
A declaration is a definition unless:
. it declares a function without specifying its body,
. it contains an extern specifier and no initializer or function body,
. it is the declaration of a static class data member without a class definition,
it is a class name definition,
it is a typedef declaration.
A definition is a declaration unless:
. it defines a static class data member,
. it defines a non-inline member function.
41. What is cloning?
Answer:
An object can carry out copying in two ways i.e. it can set itself to be a copy of another object, or it can return a copy of itself. The latter process is called cloning.
42. Describe the main characteristics of static functions.
Answer:
The main characteristics of static functions include,
. It is without the a this pointer,
. It can't directly access the non-static members of its class
. It can't be declared const, volatile or virtual.
. It doesn't need to be invoked through an object of its class, although for convenience, it may.
43. Will the inline function be compiled as the inline function always? Justify.
Answer:
An inline function is a request and not a command. Hence it won't be compiled as an inline function always.
Explanation:
Inline-expansion could fail if the inline function contains loops, the address of an inline function is used, or an inline function is called in a complex expression. The rules for inlining are compiler dependent.
44. Define a way other than using the keyword inline to make a function inline.
Answer:
The function must be defined inside the class.
45. How can a '::' operator be used as unary operator?
Answer:
The scope operator can be used to refer to members of the global namespace. Because the global namespace doesn’t have a name, the notation :: member-name refers to a member of the global namespace. This can be useful for referring to members of global namespace whose names have been hidden by names declared in nested local scope. Unless we specify to the compiler in which namespace to search for a declaration, the compiler simple searches the current scope, and any scopes in which the current scope is nested, to find the declaration for the name.
46. What is placement new?
Answer:
When you want to call a constructor directly, you use the placement new. Sometimes you have some raw memory that's already been allocated, and you need to construct an object in the memory you have. Operator new's special version placement new allows you to do it.
class Widget
{
public :
Widget(int widgetsize);
...
Widget* Construct_widget_int_buffer(void *buffer,int widgetsize)
{
return new(buffer) Widget(widgetsize);
}
};
This function returns a pointer to a Widget object that's constructed within the buffer passed to the function. Such a function might be useful for applications using shared memory or memory-mapped I/O, because objects in such applications must be placed at specific addresses or in memory allocated by special routines.
OOAD
1. What do you mean by analysis and design?
Analysis:
Basically, it is the process of determining what needs to be done before how it should be done. In order to accomplish this, the developer refers the existing systems and documents. So, simply it is an art of discovery.
Design:
It is the process of adopting/choosing the one among the many, which best accomplishes the users needs. So, simply, it is compromising mechanism.
2. What are the steps involved in designing?
Before getting into the design the designer should go through the SRS prepared by the System Analyst.
The main tasks of design are Architectural Design and Detailed Design.
In Architectural Design we find what are the main modules in the problem domain.
In Detailed Design we find what should be done within each module.
3. What are the main underlying concepts of object orientation?
Objects, messages, class, inheritance and polymorphism are the main concepts of object orientation.
4. What do u meant by "SBI" of an object?
SBI stands for State, Behavior and Identity. Since every object has the above three.
State:
It is just a value to the attribute of an object at a particular time.
. Behaviour:
It describes the actions and their reactions of that object.
. Identity:
An object has an identity that characterizes its own existence. The identity makes it possible to distinguish any object in an unambiguous way, and independently from its state.
5. Differentiate persistent & non-persistent objects?
Persistent refers to an object's ability to transcend time or space. A persistent object stores/saves its state in a permanent storage system with out losing the information represented by the object.
A non-persistent object is said to be transient or ephemeral. By default objects are considered as non-persistent.
6. What do you meant by active and passive objects?
Active objects are one which instigate an interaction which owns a thread and they are responsible for handling control to other objects. In simple words it can be referred as client.
Passive objects are one, which passively waits for the message to be processed. It waits for another object that requires its services. In simple words it can be referred as server.
Diagram:
client server
(Active) (Passive)
7. What is meant by software development method?
Software development method describes how to model and build software systems in a reliable and reproducible way. To put it simple, methods that are used to represent ones' thinking using graphical notations.
8. What are models and meta models?
Model:
It is a complete description of something (i.e. system).
Meta model:
It describes the model elements, syntax and semantics of the notation that allows their manipulation.
9. What do you meant by static and dynamic modeling?
Static modeling is used to specify structure of the objects that exist in the problem domain. These are expressed using class, object and USECASE diagrams.
But Dynamic modeling refers representing the object interactions during runtime. It is represented by sequence, activity, collaboration and statechart diagrams.
10. How to represent the interaction between the modeling elements?
Model element is just a notation to represent (Graphically) the entities that exist in the problem domain. e.g. for modeling element is class notation, object notation etc.
Relationships are used to represent the interaction between the modeling elements.
The following are the Relationships.
Association: Its' just a semantic connection two classes.
e.g.:
Aggregation: Its' the relationship between two classes which are related in the fashion that master and slave. The master takes full rights than the slave. Since the slave works under the master. It is represented as line with diamond in the master area.
ex:
car contains wheels, etc.
car
. Containment: This relationship is applied when the part contained with in the whole part, dies when the whole part dies.
It is represented as darked diamond at the whole part.
example:
class A{
//some code
};
class B
{
A aa; // an object of class A;
// some code for class B;
};
In the above example we see that an object of class A is instantiated with in the class B. so the object class A dies when the object class B dies.we can represnt it in diagram like this.
. Generalization: This relationship used when we want represents a class, which captures the common states of objects of different classes. It is represented as arrow line pointed at the class, which has captured the common states.
. Dependency: It is the relationship between dependent and independent classes. Any change in the independent class will affect the states of the dependent class.
DIAGRAM:
class A class B
11. Why generalization is very strong?
Even though Generalization satisfies Structural, Interface, Behaviour properties. It is mathematically very strong, as it is Antisymmetric and Transitive.
Antisymmetric: employee is a person, but not all persons are employees. Mathematically all As’ are B, but all Bs’ not A.
Transitive: A=>B, B=>c then A=>c.
A. Salesman.
B. Employee.
C. Person.
Note: All the other relationships satisfy all the properties like Structural properties, Interface properties, Behaviour properties.
12. Differentiate Aggregation and containment?
Aggregation is the relationship between the whole and a part. We can add/subtract some properties in the part (slave) side. It won't affect the whole part.
Best example is Car, which contains the wheels and some extra parts. Even though the parts are not there we can call it as car.
But, in the case of containment the whole part is affected when the part within that got affected. The human body is an apt example for this relationship. When the whole body dies the parts (heart etc) are died.
13. Can link and Association applied interchangeably?
No, You cannot apply the link and Association interchangeably. Since link is used represent the relationship between the two objects.
But Association is used represent the relationship between the two classes.
link :: student:Abhilash course:MCA
Association:: student course
14. what is meant by "method-wars"?
Before 1994 there were different methodologies like Rumbaugh, Booch, Jacobson, Meyer etc who followed their own notations to model the systems. The developers were in a dilemma to choose the method which best accomplishes their needs. This particular span was called as "method-wars"
15. Whether unified method and unified modeling language are same or different?
Unified method is convergence of the Rumbaugh and Booch.
Unified modeling lang. is the fusion of Rumbaugh, Booch and Jacobson as well as Betrand Meyer (whose contribution is "sequence diagram"). Its' the superset of all the methodologies.
16. Who were the three famous amigos and what was their contribution to the object community?
The Three amigos namely,
. James Rumbaugh (OMT): A veteran in analysis who came up with an idea about the objects and their Relationships (in particular Associations).
. Grady Booch: A veteran in design who came up with an idea about partitioning of systems into subsystems.
. Ivar Jacobson (Objectory): The father of USECASES, who described about the user and system interaction.
17. Differentiate the class representation of Booch, Rumbaugh and UML?
If you look at the class representaiton of Rumbaugh and UML, It is some what similar and both are very easy to draw.
Representation: OMT UML.
Diagram:
Booch: In this method classes are represented as "Clouds" which are not very easy to draw as for as the developer's view is concern.
Diagram:
18. What is an USECASE? Why it is needed?
A Use Case is a description of a set of sequence of actions that a system performs that yields an observable result of value to a particular action.
In SSAD process <=> In OOAD USECASE. It is represented elliptically.
Representation:
19. Who is an Actor?
An Actor is someone or something that must interact with the system.In addition to that an Actor initiates the process(that is USECASE).
It is represented as a stickman like this.
Diagram:
20. What is guard condition?
Guard condition is one, which acts as a firewall. The access from a particular object can be made only when the particular condition is met.
For Example,
customer check customer number ATM.
Here the object on the customer accesses the ATM facility only when the guard condition is met.
21. Differentiate the following notations?
I: :obj1 :obj2
II: :obj1 :obj2
In the above representation I, obj1 sends message to obj2. But in the case of II the data is transferred from obj1 to obj2.
22. USECASE is an implementation independent notation. How will the designer give the implementation details of a particular USECASE to the programmer?
This can be accomplished by specifying the relationship called "refinement” which talks about the two different abstraction of the same thing.
Or example,
calculate pay calculate
class1 class2 class3
23. Suppose a class acts an Actor in the problem domain, how to represent it in the static model?
In this scenario you can use “stereotype”. Since stereotype is just a string that gives extra semantic to the particular entity/model element. It is given with in the << >>.
class A
<< Actor>>
attributes
methods.
24. Why does the function arguments are called as "signatures"?
The arguments distinguish functions with the same name (functional polymorphism). The name alone does not necessarily identify a unique function. However, the name and its arguments (signatures) will uniquely identify a function.
In real life we see suppose, in class there are two guys with same name, but they can be easily identified by their signatures. The same concept is applied here.
ex:
class person
{
public:
char getsex();
void setsex(char);
void setsex(int);
};
In the above example we see that there is a function setsex() with same name but with different signature.
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