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Java question bank

http://cquestionbank.blogspot.in/2011/02/java-question-bank.html Core java basics questions bank for quiz and answers

(1)

public class ArrayDemo {

public static void main(String[] args) {

int [] arr1,arr2;

arr1=new int[1];

arr2=new int[2];

arr1[0]='\n';

arr2[0]='a';

System.out.print(arr2[0]%arr1[0]);

}

}

What will be output of above program?

(a)6

(b)7

(c)0

(d)Compiler error

Answer: (d)

(2)

class Try

{

public int a;

}

public class ClassDemo {

http://cquestionbank.blogspot.in/2011/02/java-question-bank.html

public static void main(String[] args){

Try t=new Try();

t.a=4>>>2+3%5;

System.out.println(t.a);

delete t;

}

}


(a)1

(b)4

(c)19

(d)Compiler error

Answer: (d)

(3)What will be output of following program?

public class EnumTest {


char c=65;

System.out.print(c);

}

}

(a)65

(b)’65’

(c)A

(d)Compiler error

Answer: (c)

Explanation:

(4)

public class BitwiseOpe {


int a=-0x20;

int b=a<<<3;

System.out.println(b);

}

}

What will output when you compile and run the above code?

(a)0

(b)4

(c)32

(d)Compiler error

Answer: (d)

(5) public class Overloading {

int a='\u0021';


Overloading t=new Overloading();

t.incrementor(t);

System.out.print(t.a);

}

void incrementor (Overloading tt)

{

byte a=6;

tt.a+=++this.a + ++a + ++tt.a;

}

}


(a)111

(b)109

(c)80

(d)Compiler error

Answer: (b)

(6)

public class ArrayDemo {


int []arr,a;

arr=new int[2];

a=011;

arr[0]=arr[1]=a;

System.out.print(arr[0]+arr[1]);

}

}


(a)22

(b)18

(c)022

(d)Compiler error

Answer: (d)

(7)

class Try

{

public int a;

}



a=4>>>2+3%5;

System.out.println(a);

}

}


(a)1

(b)4

(c)17

(d)Compiler error

Answer: (d)

(8)What will be output of following program?

public class Float {


float f=5.5f;

long l=25L,m;

long m=l+f;

System.out.print(m);

}

}

(a)30

(b)31

(c)30.0

(d)Compiler error

Answer: (d)

Explanation:

(9)



int a=-0x20;

int b=a>>2;


}

}


(a)-8

(b)-128

(c)128

(d)Compiler error

Answer: (a)

(10)

public class Overloading {


int a='\u0020';

Overloading t=new Overloading();

t.incrementor(a);

System.out.print(a);

}

void incrementor(int a)

{

a+=++a + ++a + ++a;

}

}


(a)20

(b)32

(c)198

(d)Compiler error

Answer: (c)

(11)

public class ControlStatement {


int a=25;

if(a>10)

System.out.print("ok");

elseif(true)

System.out.print("bye");

}

}


(a) ok

(b) bye

(c) okbye

(d)Compiler error

Answer: (d)

(12)



String str=display();

System.out.print(str);

}

String display()

{

return "I know c#";

}

}


(a) I know c#

(b) “I know c#”

(c) null

(d)Compiler error

Answer: (d)

(13)

public class Literal {


byte a=0x11;

byte b=0X22;

int c=b-a+~2;

System.out.print(c);

}

}


(a)9

(b)8

(c)14

(d) Compiler error

Answer: (c)

Explanation:

(14)



byte a=12;

int b=a>>>1;


}

}


(a)-12

(b)6

(c)12

(d)Compiler error

Answer: (b)

(15)

public class Overloading {

int a='\u0021';

public static void main(String[] args) throws Exception {

Overloading t;

t=new Overloading().incrementor();

System.out.print(t.a);

}

Overloading incrementor()

{

Overloading tt=new Overloading();

byte a=6;

tt.a-=++this.a + ++a + ++tt.a;

return tt;

}

}


(a)-41

(b)-42

(c)-43

(d)Compiler error

Answer: (b)

Answers of the bewlo questions available at http://www.indiabix.com/java-programming/operators-and-assignments/

1. What will be the output of the program?

class PassA{ public static void main(String [] args) { PassA p = new PassA(); p.start(); }

void start() { long [] a1 = {3,4,5}; long [] a2 = fix(a1); System.out.print(a1[0] + a1[1] + a1[2] + " "); System.out.println(a2[0] + a2[1] + a2[2]); }

long [] fix(long [] a3) { a3[1] = 7; return a3; }}

A.12 15 B.15 15C.3 4 5 3 7 5 D.3 7 5 3 7 5

What will be the output of the program?

class Test{ public static void main(String [] args) { Test p = new Test(); p.start(); }

void start() { boolean b1 = false; boolean b2 = fix(b1); System.out.println(b1 + " " + b2); }

boolean fix(boolean b1)

http://www.indiabix.com/java-programming/operators-and-assignments/

http://www.indiabix.com/java-programming/operators-and-assignments/

{ b1 = true; return b1; }}

A.

true true B.false true

C.true false D.false false


class PassS{ public static void main(String [] args) { PassS p = new PassS(); p.start(); }

void start() { String s1 = "slip"; String s2 = fix(s1); System.out.println(s1 + " " + s2); }

String fix(String s1) { s1 = s1 + "stream"; System.out.print(s1 + " "); return "stream"; }}

A.

slip stream

B.slipstream streamC.stream slip streamD.

slipstream slip stream


class BitShift{ public static void main(String [] args) {

int x = 0x80000000; System.out.print(x + " and "); x = x >>> 31; System.out.println(x); }}

A.

-2147483648 and 1

B.0x80000000 and 0x00000001C.-2147483648 and -1D.

1 and -2147483648


class Equals{ public static void main(String [] args) { int x = 100; double y = 100.1; boolean b = (x = y); /* Line 7 */ System.out.println(b); }}

A.

true

B.falseC.Compilation failsD.

An exception is thrown at runtime


class Test{ public static void main(String [] args) { int x=20; String sup = (x < 15) ? "small" : (x < 22)? "tiny" : "huge"; System.out.println(sup); }}

A.small B.tinyC.huge D.Compilation fails


class Test{ public static void main(String [] args) { int x= 0; int y= 0; for (int z = 0; z < 5; z++) { if (( ++x > 2 ) && (++y > 2)) { x++; } } System.out.println(x + " " + y); }}

A.5 2 B.5 3C.6 3 D.6 4


class Test{ public static void main(String [] args) { int x= 0; int y= 0; for (int z = 0; z < 5; z++) { if (( ++x > 2 ) || (++y > 2)) { x++; } } System.out.println(x + " " + y); }}

A.5 3 B.8 2C.8 3 D.8 5


class Bitwise{ public static void main(String [] args)

{ int x = 11 & 9; int y = x ^ 3; System.out.println( y | 12 ); }}

A.

0 B.7

C.8 D.14


class SSBool{ public static void main(String [] args) { boolean b1 = true; boolean b2 = false; boolean b3 = true; if ( b1 & b2 | b2 & b3 | b2 ) /* Line 8 */ System.out.print("ok "); if ( b1 & b2 | b2 & b3 | b2 | b1 ) /*Line 10*/ System.out.println("dokey"); }}

A.

ok

B.dokeyC.ok dokeyD.

No output is produced

E.Compilation error


class SC2{ public static void main(String [] args) { SC2 s = new SC2(); s.start(); }

void start() { int a = 3; int b = 4; System.out.print(" " + 7 + 2 + " "); System.out.print(a + b); System.out.print(" " + a + b + " ");

System.out.print(foo() + a + b + " "); System.out.println(a + b + foo()); }

String foo() { return "foo"; }}

A.

9 7 7 foo 7 7foo

B.72 34 34 foo34 34fooC.9 7 7 foo34 34fooD.

72 7 34 foo34 7foo


class Test{ static int s; public static void main(String [] args) { Test p = new Test(); p.start(); System.out.println(s); }

void start() { int x = 7; twice(x); System.out.print(x + " "); }

void twice(int x) { x = x*2; s = x; }}

A.

7 7 B.7 14

C.14 0 D.14 14


class Two{ byte x;}

class PassO{ public static void main(String [] args) { PassO p = new PassO(); p.start(); }

void start() { Two t = new Two(); System.out.print(t.x + " "); Two t2 = fix(t); System.out.println(t.x + " " + t2.x); }

Two fix(Two tt) { tt.x = 42; return tt; }}

A.

null null 42 B.0 0 42

C.0 42 42 D.0 0 0


class BoolArray{ boolean [] b = new boolean[3]; int count = 0;

void set(boolean [] x, int i) { x[i] = true; ++count; }

public static void main(String [] args) { BoolArray ba = new BoolArray(); ba.set(ba.b, 0); ba.set(ba.b, 2); ba.test();

}

void test() { if ( b[0] && b[1] | b[2] ) count++; if ( b[1] && b[(++count - 2)] ) count += 7; System.out.println("count = " + count); }}

A.

count = 0 B.count = 2

C.count = 3 D.count = 4


public class Test{ public static void leftshift(int i, int j) { i <<= j; } public static void main(String args[]) { int i = 4, j = 2; leftshift(i, j); System.out.printIn(i); }}

A.

2 B.4

C.8 D.16

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