Java MCQ

Java is a high-level, general-purpose, object-oriented programming language. It is easy and used to develop any kind of program. Apart from this, it can also be used in Android development.

Editions of Java

  • Java mainly has three editions -
  • Java Standard Edition(SE): develop applications that run on the desktop.
  • Java Enterprise Edition(EE): develop server-side applications.
  • Java Micro Edition(ME): develop applications for mobile devices.

Java Development Kit

  • Set of programs that enable us to develop our programs.
  • Contains JRE(Java Runtime Environment) that is used to run our programs.

Java Architecture

  • Java Architecture consists of three main components:
  • JVM: One of the main features of Java is Write Once Run Anywhere, i.e. it is platform-independent. It can run on any OS irrespective of the environment because of Java Virtual Machine.
  • JRE: Java Runtime Environment provides an environment for the Java programs to be executed.
  • JDK: It is the software development environment that is mainly used in the development of Java applications and applets.

Java MCQ Questions

1. 

Number of primitive data types in Java are?

6

7

8

9

2. 

What is the size of float and double in java?

32 and 64

32 and 32

64 and 64

64 and 32

3. 

Automatic type conversion is possible in which of the possible cases?

Byte to int

Int to long

Long to int

Short to int

4. 

Find the output of the following code.

int Integer = 24;
char String  = ‘I’;
System.out.print(Integer);
System.out.print(String);

Compile error

Throws exception

I

24 I

5. 

Find the output of the following program.

public class Solution{
       public static void main(String[] args){
                     short x = 10;
                     x =  x * 5;
                     System.out.print(x);
       }
}

50

10

Compile error

Exception

6. 

Find the output of the following program.

public class Solution{
       public static void main(String[] args){
                     byte x = 127;
                     x++;
                     x++;
                     System.out.print(x);
       }
}

-127

127

129

2

7. 

Select the valid statement.

char[] ch = new char(5)

char[] ch = new char[5]

char[] ch = new char()

char[] ch = new char[]

8. 

Find the output of the following program.

public class Solution{
       public static void main(String[] args){
               int[]  x = {120, 200, 016};
               for(int i = 0; i < x.length; i++){
                        System.out.print(x[i] + “ “);
               }                   
       }
}

120 200 016

120 200 14

120 200 16

None

9. 

When an array is passed to a method, what does the method receive?

The reference of the array

A copy of the array

Length of the array

Copy of first element

10. 

Select the valid statement to declare and initialize an array.

int[] A = {}

int[] A = {1, 2, 3}

int[] A = (1, 2, 3)

int[][] A = {1,2,3}

11. 

Find the value of A[1] after execution of the following program.

int[] A = {0,2,4,1,3};
for(int i = 0; i < A.length; i++){
A[i] = A[(A[i] + 3) % A.length];
}

0

1

2

3

12. 

Arrays in java are-

Object references

objects

Primitive data type

None

13. 

When is the object created with new keyword?

At run time

At compile time

Depends on the code

None

14. 

Identify the corrected definition of a package.

A package is a collection of editing tools

A package is a collection of classes

A package is a collection of classes and interfaces

A package is a collection of interfaces

15. 

Identify the correct restriction on static methods.

  1. They must access only static data
  2. They can only call other static methods.
  3. They cannot refer to this or super.

I and II

II and III

Only III

I, II and III

16. 

Identify the keyword among the following that makes a variable belong to a class,rather than being defined for each instance of the class.

final

static

volatile

abstract

17. 

Identify what can directly access and change the value of the variable res.

package com.mypackage;
public class Solution{
       private int res = 100;
}

Any class

Only Solution class

Any class that extends Solution

None

18. 

In which of the following is toString() method defined?

java.lang.Object

java.lang.String

java.lang.util

None

19. 

compareTo() returns

True

False

An int value

None

20. 

Identify the output of the following program.

String str = “abcde”;
System.out.println(str.substring(1, 3));

abc

bc

bcd

cd

21. 

Identify the output of the following program.

String str = “Hellow”;
System.out.println(str.indexOf(‘t));

0

1

true

-1

22. 

Identify the output of the following program.

Public class Test{
          Public static void main(String argos[]){
                   String str1 = “one”;
                   String str2 = “two”;
                   System.out.println(str1.concat(str2));
          }
}

one

two

onetwo

twoone

23. 

What does the following string do to given string str1.

String str1 = “Interviewbit”.replace(‘e’,’s’);

Replaces single occurrence of ‘e’ to ‘s’.

Replaces all occurrences of ‘e’ to ‘s’.

Replaces single occurrence of ‘s’ to ‘e’.

None.

24. 

To which of the following does the class string belong to.

java.lang

java.awt

java.applet

java.string

25. 

How many objects will be created in the following?

String a = new String(“Interviewbit”);
String b = new String(“Interviewbit”);
Strinc c = “Interviewbit”;
String d = “Interviewbit”;

2

3

4

None

26. 

Total constructor string class have?

3

7

13

20

27. 

Find the output of the following code.

int ++a = 100;
System.out.println(++a);

101

Compile error as ++a is not valid identifier

100

None

28. 

Find the output of the following code.

if(1 + 1 + 1 + 1 + 1 == 5){
  System.out.print(“TRUE”);
}
else{
  System.out.print(“FALSE”);
}

TRUE

FALSE

Compile error

None

29. 

Find the output of the following code.

Public class Solution{
      Public static void main(String… argos){
             Int x = 5;
             x * = (3 + 7);
             System.out.println(x);

50

22

10

None

30. 

Identify the return type of a method that does not return any value.

int

void

double

None

31. 

Output of Math.floor(3.6)?

3

3.0

4

4.0

32. 

Where does the system stores parameters and local variables whenever a method is invoked?

Heap

Stack

Array

Tree

33. 

Identify the modifier which cannot be used for constructor.

public

protected

private

static

34. 

What is the variables declared in a class for the use of all methods of the class called?

Object

Instance variables

Reference variable

None

35. 

What is the implicit return type of constructor?

No return type

A class object in which it is defined

void

None

36. 

When is the finalize() method called?

Before garbage collection

Before an object goes out of scope

Before a variable goes out of scope

None

37. 

Identify the prototype of the default constructor.

Public class Solution {}

Solution(void)

Solution()

public Solution(void)

public Solution()

38. 

Identify the correct way of declaring constructor.

Public class Solution {}

Solution(){}

public Solution(){}

Solution(void){}

Both (A) and (B)

39. 

Find the output of the following code.

Public class Solution{
         Public static void main(String args[]){
                 Int i;
                 for(i = 1; i < 6; i++){ 
                     if(i > 3) continue;
                 }
                 System.out.println(i);
          }
}

3

4

5

6

40. 

How many times will “Interviewbit” be printed.

Int count = 0;
do{
  System.out.println(“Interviewbit”);
  count++;
} while(count < 10);

8

9

10

11

41. 

Identify the infinite loop.

for(; ;)

for(int i = 0; i < 1; i--)

for(int i = 0; ;i++)

All of the above

42. 

What is Runnable?

Abstract class

Interface

Class

Method

43. 

Exception created by try block is caught in which block

catch

throw

final

none

44. 

Which of the following exception is thrown when divided by zero statement is executed?

NullPointerException

NumberFormatException

ArithmeticException

None

45. 

Where is System class defined?

java.lang.package

java.util.package

java.io.package

None

46. 

Identify the interface which is used to declare core methods in java?

Comparator

EventListener

Set

Collection

47. 

Which of the following statements are true about finalize() method?

It can be called Zero or one times

It can be called Zero or more times

It can be called Exactly once

 It can be calledOne or more times

48. 

What does the operator >>>> do?

Right shift operator

Left shift operator

Zero fill left shift

Zero fill right shift

49. 

Identify the incorrect Java feature.

Object oriented

Use of pointers

Dynamic

Architectural neural

50. 

Which of the following is used to find and fix bugs in the program?

JDK

JRE

JVM

JDB