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programming languages Online Quiz - 63

Description: programming languages Online Quiz - 63
Number of Questions: 20
Created by:
Tags: programming languages

public class Play { public static void main(String[] args) { int[][] a = {{5,2,4,7}, {9,2}, {3,4}}; int[] b = a[1]; int[][] b1= new int[3][]; int a2 = b[2]; System.out.println(a2); } }

  1. 2

  2. 4

  3. Exception

  4. Compilation error

  5. 9

Answer: 3

public class Top { private int i; Top(int i) {this.i=i; } public int getValue(){ return this.i; } } class Bottom{ public static void main(String[] args) { Top tp = new Top(5); String j = Integer.toString(tr.getValue()); tp.i=15; System.out.println( tp.i + j); } }

  1. 155

  2. Compilation error

  3. Exception

  4. 20

  5. 5 5

Answer: 2

class Root { int bark=10; public void get(){ System.out.println("Root"); } } public class Tree extends Root{ public void get(){ bark =15; System.out.println("Tree"); } public static void main(String[] args){ Tree t = new Tree(); Root r = new Root(); Root t1= new Tree(); r.get(); t.get(); t1.get(); System.out.println(t.bark); System.out.println(t1.bark); System.out.println(r.bark); } }

  1. Root Tree Tree 15 15 15

  2. Root Tree Tree 10 15 15

  3. Root Tree Root 15 15 10

  4. Root Tree Tree 15 15 10

  5. Root Tree Tree 15 10 10

Answer: 4

public class Fun { public static void main(String[] args){ int x=0; boolean b=true; String str; str=(b)?"success": (x=0)?"Failure":"Neither"; System.out.println(str); } }

  1. Failure

  2. success

  3. Exception will be thrown

  4. Compilation error

  5. Neither

Answer: 4

class test{} class tester extends test{ public static void main(String[] args) { test t1 = new tester(); test t2 = new test(); tester t3 = new tester(); System.out.println( t1 instanceof tester); System.out.println( t2 instanceof tester); System.out.println( t3 instanceof tester); System.out.println( t1 instanceof test); System.out.println( t2 instanceof test); System.out.println( t3 instanceof test); }

  1. True False True True True True

  2. True False False True True True

  3. True False True True True False

  4. True False True True False True

Answer: 1

Which class is the immediate superclass of the Container class?

  1. Frame

  2. Component

  3. Public

  4. Super

Answer: 2

Checked Exceptions are

  1. all sub-classes of Throwable

  2. not the sub classes of RuntimeException

  3. all sub-classes of Error

  4. None of these

Answer: 2

Which abstract class is the super class of all classes used for writing characters. Select the one correct answer.

  1. FileWriter

  2. CharWriter

  3. Writer

  4. OutputStream

  5. FileOutputStream

Answer: 3

A class inherit the constructors of its superclass?

  1. True

  2. False

Answer: 2

Can a Byte object be cast to a double value?

  1. True

  2. False

Answer: 2

Which containers may have a MenuBar?

  1. Panel

  2. Frame

  3. Class

  4. JVM

Answer: 2

What is the purpose of the Runtime class?

  1. To provide access to the Java runtime system.

  2. To avoid run time exception.

  3. To provide the capability to execute code no matter whether or not an exception is thrown or caught.

  4. Both 2 & 3

Answer: 1

Garbage collection guarantee that a program will not run out of memory.

  1. True

  2. False

Answer: 2

A lock can be acquired in a class.

  1. True

  2. False

Answer: 1

At first JAVA was named as______ .

  1. Fusion

  2. Gabriel

  3. Oak

  4. Globe

Answer: 3

The following line of code is valid. int x = 9; byte b = x;

  1. True

  2. False

Answer: 2

Which of the following keywords is used to invoke a method in the parent class?

  1. this

  2. super

  3. final

  4. static

Answer: 2

Assertions are used to enforce all but which of the following?

  1. Preconditions

  2. Postconditions

  3. Exceptions

  4. Class invariants

Answer: 3

The developer can force garbage collection by calling System.gc().

  1. True

  2. False

Answer: 2

What modifiers may be used with an interface declaration

  1. Public

  2. Private

  3. Abstract

  4. Protected

Answer: 1,3
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