Java MCQ – Interfaces – Part 1

This collection of Java Multiple Choice Questions and Answers (MCQs): Quizzes & Practice Tests with Answer focuses on “Java Interfaces”.
 

1. What keyword is used to declare an interface in Java?

A class

B interface

C implements

D abstract

interface A {
}

2. Java interface can contain ____________

A Final variables

B Abstract methods

C Non-abstract methods

D Final variables and abstract methods

interface interfaceName{
   // Final or static variables
   datatype variableName = value;
   // Abstract method declarations
   returntype methodName([Parameters...]);
}

3. What is the correct way to implement an interface?

Example, ‘Operation’ interface implements ‘Add’ class.
 
A class Add implements Operation{}

B class Add extends Operation{}

C class Add import Operation{}

D None of the above

4. Which of the following statements applies to methods of an interface in Java?

A An interface can only contain abstract methods.

B You can define a method in an interface

C Private and protected access modifiers can also be used to declare methods in an interface

D None of the above

5. Which is the correct declaration to implement two interfaces?

A class A implements B, implements C {}

B class A implements B, C {}

C class A implements B C {}

D None of the above

6. Can we declare an interface as final?

A Yes

B No

7. All methods must be implemented in an interface?

A Yes

B No

8. What does an interface contain?

A Method definition

B Method declaration

C Declaration and definition of the method

D Method name

9. What kind of methods does an interface contain by default?

A abstract

B static

C final

D private

10. What type of variable can be defined in an interface?

A public static

B private final

C public final

D static final

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