Java Variables

Here are 10 essential multiple-choice questions on Java Variables, covering key concepts with practical examples.

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Question 1

Which of the following is a valid way to declare a variable in Java?

  • int number = 10;

  • var number = 10;

  • Integer number = 10;

  • All of the above


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Question 2

What will be the output of the following code?

Java 
public class Geeks {
    public static void main(String[] args) {
        int a;
        System.out.println(a);
    }
}


  • 0

  • Compilation Error

  • Runtime Error

  • Undefined Behavior

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Question 3

Which of the following is true about variable names in Java?


  • Variable names can start with a number

  • Variable names can contain special characters like @ or #

  • Variable names are case-sensitive


  • Variable names can be a Java keyword


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Question 4

What is the default value of a boolean instance variable in Java?


  • true

  • false

  • null


  • Compilation Error


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Question 5

What will be the output of the following Java program?

Java 
public class Main {
    static int x;
    public static void main(String[] args) {
        System.out.println(x);
    }
}


  • 0

  • Compilation Error


  • Runtime Error


  • Undefined Behavior

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Question 6

What is the correct way to declare a constant variable in Java?


  • final int MAX = 100;

  • const int MAX = 100;

  • int const MAX = 100;


  • MAX = 100;

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Question 7

What will be the output of this code?

Java 
public class Example {
    int num = 5;
    public static void main(String[] args) {
        Example obj = new Example();
        System.out.println(obj.num);
    }
}


  • Compilation Error

  • 5

  • Runtime Error

  • Undefined Behavior

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Question 8

Which of the following statements about var keyword is FALSE?


  • var can be used for local variables

  • var can be used for instance variables


  • var must be initialized at the time of declaration

  • var is introduced in Java 10

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Question 9

What will be the output of this Java program?

Java 
public class Demo {
    public static void main(String[] args) {
        int x = 10;
        {
            int x = 20;
            System.out.println(x);
        }
    }
}


  • 20

  • 10

  • Compilation Error


  • Runtime Error


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Question 10

Which of the following statements is correct?


  • Static variables are shared among all objects of a class

  • Local variables are automatically initialized

  • Instance variables cannot be final

  • A final variable can be reassigned

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There are 10 questions to complete.

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