Quiz for Default & Static Methods in Interfaces

Q1: What keyword is used to define a default method in an interface?

A. static B. default C. abstract D. public

Q2: Can default methods be overridden in implementing classes?

A. Yes B. No C. Only if abstract D. Only in abstract classes

Q3: What happens if two interfaces have same default method?

A. Compilation error B. Runtime error C. Ambiguity must be resolved in implementing class D. Ignored

Q4: Which of these can call a static method in an interface?

A. Object of implementing class B. Using interface name C. Any object D. None of the above

Q5: Are default methods allowed in abstract classes?

A. Yes B. No C. Only static D. Only abstract

Q6: Can static methods in interfaces be inherited?

A. Yes B. No C. Only default methods are inherited D. They are inherited as abstract

Q7: Which of these is a benefit of default methods?

A. Allows backward compatibility B. Replaces abstract methods C. Improves performance D. Adds polymorphism

Q8: Which method is used to override a default method?

A. super.method() B. interfaceName.super.method() C. this.method() D. default.method()

Q9: Can a default method access private fields of a class?

A. Yes B. No C. Only static fields D. Only final fields

Q10: Which of these is NOT allowed in interfaces from Java 8?

A. Default methods B. Static methods C. Constructors D. Abstract methods

Q11: What access modifier is used for default methods?

A. public B. default C. private D. protected

Q12: Which Java version introduced static methods in interfaces?

A. Java 6 B. Java 7 C. Java 8 D. Java 9

Q13: Can interfaces have private methods in Java 8?

A. Yes B. No C. Only in abstract class D. Only with static modifier

Q14: Can default method call a static method from the same interface?

A. Yes, directly B. Yes, via InterfaceName C. No D. Only using reflection

Q15: What is the output of calling an unimplemented default method?

A. Compile-time error B. Runtime error C. Method executes normally D. Method is abstract

Q16: Default methods are mainly introduced to:

A. Break backward compatibility B. Provide default implementation C. Replace abstract classes D. Improve encapsulation

Q17: A static method in an interface is:

A. Inherited by implementing class B. Can be overridden C. Cannot be overridden D. Used in constructors

Q18: What happens if class implements two interfaces with same default method?

A. Class must override it B. Compile-time error C. Last loaded interface used D. First declared interface used

Q19: Which keyword is NOT used with default methods?

A. default B. public C. synchronized D. void

Q20: Which is a correct example of a default method?

A. public void walk(); B. static void walk() { } C. default void walk() { System.out.println("walking"); } D. abstract walk();