Variables and Data Types – Multiple Choice Questions (MCQs)

1. 13. What is the default value of a reference data type in Java?

   • A. 0
   • B. null
   • C. undefined
   • D.

2. 14. Which keyword is used to declare a variable as a constant in Java?

   • A. const
   • B. immutable
   • C. readonly
   • D. final

3. 15. What is the scope of a local variable in Java?

   • A. Accessible from anywhere in the class
   • B. Accessible only within the method where it is declared
   • C. Accessible within the same package
   • D. Accessible within the same class

4. 16. What is the scope of an instance variable in Java?

   • A. Accessible only within the method where it is declared
   • B. Accessible only within the class where it is declared
   • C. Accessible to all instances of the class
   • D. Accessible within the same package

5. 17. What is the scope of a static variable in Java?

   • A. Accessible only within the method where it is declared
   • B. Accessible only within the class where it is declared
   • C. Accessible to all instances of the class and the class itself
   • D. Accessible within the same package

6. 18. Which of the following is a valid variable declaration in Java?

   • A. int x;
   • B. variable y = 10;
   • C. String "hello";
   • D. float 3.14f;

7. 19. Which of the following is NOT a valid variable name in Java?

   • A. myVariable
   • B. _myVar
   • C. 1stVar
   • D. $myVar

8. 20. What is type casting in Java?

   • A. Converting a primitive data type to a reference type
   • B. Converting a reference type to a primitive data type
   • C. Converting a value of one data type to another
   • D. Declaring a variable without assigning a value

9. 21. What is implicit type casting (widening) in Java?

   • A. Casting from a larger data type to a smaller one
   • B. Casting from a smaller data type to a larger one
   • C. Casting between reference types
   • D. It is not allowed in Java

10. 22. What is explicit type casting (narrowing) in Java?

    • A. Casting from a smaller data type to a larger one
    • B. Casting from a larger data type to a smaller one
    • C. Casting between primitive types
    • D. It happens automatically

11. 23. Which operator is used for type casting in Java?

    • A. ()
    • B. []
    • C. {}
    • D. <>

12. 24. What will be the result of `(int) 3.14`?

    • A. 3
    • B. 3
    • C. Error
    • D. 4