Main Exam 8

Question 1 of 47

What will the following program print?

public class TestClass{ static String str; public static void main(String[] args) { System.out.println(str); }}

Select 1 correct option.a It will not compile.

b It will compile but throw an exception at runtime.

c It will print 'null'

d It will print nothing.

e None of the above.

Question 2 of 47

What will be the output of the following lines ?

System.out.println("" +5 + 6); //1 System.out.println(5 + "" +6); // 2 System.out.println(5 + 6 +""); // 3 System.out.println(5 + 6); // 4

Select 1 correct option.a 56, 56, 11, 11

b 11, 56, 11, 11

c 56, 56, 56, 11

d 56, 56, 56, 56

e 56, 56, 11, 56

Question 3 of 47

Consider the following code:

class MyRunnable implements Runnable{

public static void main(String[] args){

new Thread( new MyRunnable(2) ).start();

}public void run(int n){

for(int i=0; i<n; i++){

System.out.println("Hello World");}

}}

What will be the output when this program is compiled and run from the command line?

Select 1 correct option.a It'll print "Hello World" once.

b It'll print "Hello World" twice.

c This program will not even compile.

d This will compile but will throw an exception at runtime.

e It will compile and run but it will not print anything.

Question 4 of 47

Consider the following lines of code...

1. public void method() {2. String a,b;3. a=new String("hello world");4. b=new String("good bye");5. System.out.println(a+b+" ! ");6. a=null;7. a=b;8. System.out.println(a); }

In the absence of compiler optimization, after which earliest line the object originally referred by a is definitely eligible to be garbage collected? (Do not add spaces or dots. Just type in the number.)

Question 5 of 47

Write the name of the method used to schedule a thread for execution? (Do not enter any space or brackets.)

Question 6 of 47

The following method will compile and run without any problems.

public void switchTest(byte x){ switch(x) { case 'b': // 1 default : // 2 case -2: // 3 case 80: // 4 }}

Select 1 correct option.a True

b False

Question 7 of 47

'3b1' is the hex value for the Greek letter alpha in the Unicode. Write the Unicode literal which can be used to initialize a char variable to alpha. (Just write what should replace uuuuuu in the following statement? char alpha = 'uuuuuu' ; )

Question 8 of 47

Consider the following program... What will happen if you try to compile and run the program? public class TestClass{ public static void main(String[] args) { calculate(2); } public static void calculate(int x) { String val; switch(x) { case 2: default: val = "def";

} System.out.println(val); }}

Select 2 correct optionsa It will not compile saying that variable ' val' may not have been initialized..

b It will compile and print 'def'.

c As such it will not compile but will compile if calculate(2); is replaced by calculate(3);

d It will compile for any int values in calculate(...);

Question 9 of 47

What will be the result of compiling and running the following program ?

class NewException extends Exception {}class AnotherException extends Exception {}public class ExceptionTest{ public static void main(String[] args) throws Exception { try { m2(); } finally { m3(); } catch (NewException e){} } public static void m2() throws NewException { throw new NewException(); } public static void m3() throws AnotherException{ throw new AnotherException(); }}

Select 1 correct option.a It will compile but will throw AnotherException when run.

b It will compile but will throw NewException when run.

c It will compile and run without throwing any exceptions.

d It will not compile.


Question 10 of 47

What will be the output of the following program ?

class Test{ public static void main(String[] args) { String s = "going"; print(s, s = "gone"); } static void print(String a, String b) { System.out.println(a +", "+ b ); }}

Select 1 correct option.a It will print going, gone

b It will print gone, gone.

c It will print gone, going.

d It will print going, going.

e It will not compile.

Question 11 of 47

Using a continue in a while loop causes the loop to break the current iteration and start the next iteration of the loop.


b False

Question 12 of 47

Consider the following lines of code...

System.out.println(null + true); //1 System.out.println(true + null); //2 System.out.println(null + null); //3

Which of the following statements are correct?

Select 1 correct option.a None of the 3 lines will compile.

b All the 3 line will compile and print nulltrue, truenull and nullnull respectively.

c Line 1 and 2 won't compile but line 3 will print nullnull.

d Line 3 won't compile but line 1 and 2 will print nulltrue and truenull respectively.


Question 13 of 47

What will be the result of trying to compile and execute of the following program?

public class TestClass{ public static void main(String args[] ) { int i = 0 ; int[] iA = {10, 20} ; iA[i] = i = 30 ; System.out.println(""+ iA[ 0 ] + " " + iA[ 1 ] + " "+i) ; }}

Select 1 correct option.a It will throw ArrayIndexOutofBoundsException at Runtime.

b Compile time Error.

c It will prints 10 20 30

d It will prints 30 20 30

e It will prints 0 20 30

Question 14 of 47

What will be the result of attempting to compile and run the following code?

public class PromotionTest{ public static void main(String args[]) { int i = 5; float f = 5.5f; double d = 3.8; char c = 'a'; if (i == f) c++; if (((int) (f + d)) == ((int) f + (int) d)) c += 2; System.out.println(c); }}

Select 1 correct option.a The code will fail to compile.

b It will print d.

c It will print c.

d It will print b

e It will print a.

Question 15 of 47

Given the following declaration, select the correct way to get the size of the array, assuming that the array has been initialized.

int[] intArr;

Select 1 correct option.a intArr[ ].length( )

b intArr.length( )

c intArr.length

d intArr[ ].size( )

e intArr.size( )

Question 16 of 47

Under what situations does a class get a default constructor?

Select 1 correct option.a All classes in Java get a default constructor.

b You have to define atleast one constructor to get the default constructor.

c If the class does not define any constructors on it's own.

d All classes get default constructor from Object class.


Question 17 of 47

In java, strings are immutable. A direct implication of this is...

Select 1 correct option.a you cannot call methods like "1234".replace('1', '9');

b you cannot change a string object, once it is created.

c you can change a string object only by the means of it's methods.

d you cannot extend String class.

e you cannot compare string objects.

Question 18 of 47

The JVM exits when main() method reaches its end.


b False

Question 19 of 47

Consider the following class...

class TestClass{ int x; public static void main(String[] args) { // lot of code. }}

Select 1 correct option.a By declaring x as static, main can access this.x

b By declaring x as public, main can access this.x

c By declaring x as protected, main can access this.x

d main() cannot access this.x as it is declared now i.e. without any modifier.

e By declaring x as private, main can access this.x

Question 20 of 47

Consider the following code:

class MyThread extends Thread{

int i = 0;public void run(){

while(true){

if( i%2 == 0 ) System.out.println("Hello World");

}}

}

What will be the output when this program is compiled and run from the command line?

Select 1 correct option.a It'll keep printing "Hello World".

b It'll print "Hello World" only once.

c This program will not even compile.

d This will compile but an exception will be thrown at runtime.

e It will compile and run but it will not print anything.

Question 21 of 47

Which of these group of statements are valid?

Select 2 correct optionsa { { } }

b { continue ; }

c block : { break block ; }

d block : { continue block ; }

e The break keyword can only be used if there exists an enclosing loop construct ( i.e. while, do-while or for ).

Question 22 of 47

Consider the following hierarchy of Exception classes : Exception +-- RuntimeException +-- IndexOutOfBoundsException +-- ArrayIndexOutOfBoundsException, StringIndexOutOfBoundsException Which of the following statements are correct for a method that can throw ArrayIndexOutOfBounds as well as StringIndexOutOfBounds Exceptions but does not have try catch blocks to catch the same?

Select 3 correct optionsa The method calling this method will either have to catch these 2 exceptions or

declare them in it's throws clause.

b It's ok if it declares just 'throws ArrayIndexOutOfBoundsException'

c It must declare 'throws ArrayIndexOutOfBoundsException, StringIndexOutOfBoundsException'

d It's ok if it declares just 'throws IndexOutOfBoundsException'

e It does not need to declare any throws clause.

Question 23 of 47

Which variables of the encapsulationg class, can an inner class access if the inner class is defined in a static method of encapsulating class?

Select 2 correct optionsa All static variables

b All final instance variables

c All instance variables

d All automatic variables.

e All final automatic variables

Question 24 of 47

What is the result of compiling and running the following code ?

public class TestClass{ static int si = 10; public static void main (String args[]) { new TestClass(); } public TestClass() { System.out.println(this); } public String toString() { return "TestClass.si = "+this.si; }}

Select 1 correct option.a The class will not compile as you cannot override toString() method.

b The class will not compile as si being static, this.si is not a valid statement.

c It will print TestClass@nnnnnnnn, where nnnnnnn is the hashcode of the TestClass object refered to by 'this'.

d It will print TestClass.si = 10;


Question 25 of 47

Which of the following command line switches is required for the assert statements to be executed while running a Java class?

Select 1 correct option.a ea

b ua

c a

d No switch is needed, they are on by default.

e source

Question 26 of 47

Which of the following exceptions can be declared in the throws clause of a method overriding the method:

public void perform_work( ) throws IOException {...}

Select 4 correct optionsa IOException

b Exception

c NullPointerException

d No throws clause

e Any Subclass of IOException

Question 27 of 47

Consider :

class A { public void perform_work(){} } class B extends A { public void perform_work(){} } class C extends B { public void perform_work(){} }

How can you let perform_work() method of A to be called from an instance method in C?

Select 1 correct option.a ( (A) this ).perform_work( );

b super.perform_work( );

c super.super.perform_work( );

d this.super.perform_work( );

e It is not possible.

Question 28 of 47

What will be the result of attempting to compile and run the following class?

public class TestClass{ public static void main(String args[ ] ) { int i, j, k; i = j = k = 9; System.out.println(i); }}

Select 2 correct optionsa The code will not compile as unlike in c++, operator '=' cannot be chained.

b The code will not compile as 'j' is being used before getting initialized.

c The code will compile correctly and will display '9' when run.

d The code will not compile as 'j' and 'i' are being used before getting initialized.

e All the vairables will get a value of 9.

Question 29 of 47

Consider the following method...

public static void ifTest(boolean flag){ if (flag) //1 if (flag) //2 if (flag) //3 System.out.println("False True"); else //4 System.out.println("True False"); else //5 System.out.println("True True"); else //6 System.out.println("False False");}

Which of the following statements are correct ?

Select 2 correct options

a If run with an argument of 'false', it will print 'False False'

b If run with an argument of 'false', it will print 'True True'

c If run with an argument of 'true', it will print 'True False'

d It will never print 'True True'


Question 30 of 47

Which of the following are also called as "short circuit" logical operators?

Select 2 correct optionsa &

b ||

c &&

d |

e ^

Question 31 of 47

What will the following class print when run?

class TestClass{ int i = getInt(); int k = 20; public int getInt() { return k+1; } public static void main(String[] args) { TestClass t = new TestClass(); System.out.println(t.i+" "+t.k); }}

Select 1 correct option.a It will not even compile.

b It will compile but throw an exception at runtime.

c It will print 1 20

d It will print 21 20


Question 32 of 47

Which of the given statements are correct for a method that overrides the following method:

public void add(int a) {...}

Select 3 correct optionsa It must return void

b It may return int

c It can declare any Exception in throws clause

d It can declare any RuntimeException in throws clause.

e It can be abstract.

Question 33 of 47

Which of these statements are valid when occurring by themselves?

Select 3 correct optionsa while ( ) break ;

b do { break ; } while (true) ;

c if (true) { break ; }

d switch (1) { default : break ; }

e for ( ; true ; ) break ;

Question 34 of 47

What will be the output when running the following program?

public class TestClass{ public static void main(String args[]) { int i; int j; for (i = 0, j = 0; j < i; ++j, i++) { System.out.println(i + " " + j); } System.out.println(i + " " + j); }}

Select 1 correct option.a 0 0 will be printed twice.

b 0 0 will be printed once.

c It will keep on printing 0 0

d It will not compile.

e It will print 0 0 and then 0 1.

Question 35 of 47

Which of the following switches is/are used for controlling the execution of assertions at run time?

Select 2 correct optionsa ua

b da

c enableassertions

d assert

e keepassertions

Question 36 of 47

Which lines of code are valid declarations of a native method when occurring within the declaration of the following class?

public class TestClass{ // insert declaration of a native method here}

Select 2 correct optionsa native public void nativeMethod(int i);

b private native void nativeMethod(int i);

c protected int native nativeMethod();

d public abstract native void nativeMethod(int i);

e native int nativeMethod(int i) {}

Question 37 of 47

What should be passed as a command line parameter while running this program so that it'll print "Good Choice"?

public class TestClass{

public static void main(String args[]){

double d = Double.parseDouble(args[0]);if( Math.floor(d) == ((int)d))if( Math.ceil(d) == Math.round(d) )System.out.println("Good Choice");

}}

Select 2 correct optionsa Any positive number (e.g 4, 4.0, 4.5, 4.9 etc)

b Any positive number with no decimal part or .0 decimal part (e.g 4, 4.0 etc) but no negative number.

c Any number with no decimal part or .0 decimal part (e.g 4, 4.0, -4, -4.0 etc)

d Any number whose decimal part is bigger than or equals to .5 (eg. -3.5, -3.6, 3.5, 3.6 etc)

e Any positive number whose decimal part is bigger than or equals to .5 (eg. 3.5, 3.6 etc)

Question 38 of 47

What will the following program print?

public class TestClass{ public static void main(String[] args) { unsigned byte b = 0; b--; System.out.println(b); }}

Select 1 correct option.a 0

b -1

c 255

d -128


Question 39 of 47

Which of the following are valid escape sequences ?

Select 4 correct optionsa \b

b \t

c \f

d \r

e \x

Question 40 of 47

Which line will print the string "MUM"?

public class TestClass{

public static void main(String args []){

String s = "MINIMUM";System.out.println(s.substring(4, 7)); //1System.out.println(s.substring(5)); //2System.out.println(s.substring(s.indexOf('I', 3))); //3System.out.println(s.substring(s.indexOf('I', 4))); //4

}}

Select 1 correct option.a 1

b 2

c 3

d 4

e None of these.

Question 41 of 47

Consider the following class: public class IntPair { private int a; private int b; public void setA(int i){ this.a = i; } public int getA(){ return this.a; } public void setB(int i){ this.b = i; } public int getB(int b){ return b; } public boolean equals(Object obj) {

return ( obj instanceof obj && this.a == ((IntPair) obj).a && this.b == ((IntPair) obj).b ); } public int hashCode() { //1 } } Which of the following options would NOT be valid at //1?

Select 1 correct option.a return a;

b return a*b;

c return a+b;

d return b;

e None of these is invalid.

Question 42 of 47

Consider the following classes in one file named A.java...

abstract class A{ protected int m1(){ return 0; }}class B extends A{ int m1(){ return 1; }}

Which of the following statements are correct...

Select 1 correct option.a The code won't compile as you cannot have more than 1 class in 1 file.

b The code won't compile as class B does not override the method m1() in a right way.

c The code won't compile as A is an abstract class.

d The code won't compile as A does not have any abstract method.

e The code will compile file.

Question 43 of 47

What will be the result of attempting to run the following program?(See Exhibit)

public class StringArrayTest{ public static void main(String args[]) { String[][][] arr = { { { "a", "b" , "c"}, { "d", "e", null } }, { {"x"}, null }, {{"y"}}, { { "z","p"}, {} } }; System.out.println(arr[0][1][2]); }}

Select 1 correct option.a It will throw NullPointerBoundsException.

b It will throw ArrayIndexOutOfBoundsException.

c It will print 'null'.

d It will run without any error but will print nothing.


Question 44 of 47

You have just written a Java class named AssertTest.java that uses the assertion facility. Write down the syntax for compiling this program using Javac. [Do not write the classpath or any other switches, just use the one/ones that is/are absolutely needed. Start with: javac ...]

Question 45 of 47

What is the result of executing the following fragment of code:

boolean b1 = false;int i1 = 2;int i2 = 3;if (b1 = i1 == i2){ System.out.println("true");} else{ System.out.println("false");}

Select 1 correct option.a Compile time error.

b It will print true;

c It will print false;

d Runtime error.

e It will print nothing.

Question 46 of 47

Which of the following statments are correct regarding the equals() method?

Select 1 correct option.a It must be symetric but need not be transitive.

b It must be reflexive but need not be transitive.

c It must be symetric and transitive but not reflexive.

d If passed a null, it must return false.

e None of these.

Question 47 of 47

Consider the following program...

public class TestClass{ public int methodA(int a){ return a*2; } //1 public long methodA(int a){ return a; } //2 public static void main(String[] args) { int i = 0; i = new TestClass().methodA(2); System.out.println( i ); }}

Select 1 correct option.a Line 2 correctly overrides the method at line 1.

b Line 2 correctly overloads the method at line 1.

c There is neither overloading nor orverriding.

d The program will not compile.

e The program will compile and print 4.

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Main Exam 8