NV: Java Interface Quiz

Which of the following best describes an interface in Java?

• A blueprint for a class that cannot be instantiated.

• A concrete implementation of a class with predefined methods.

• A special type of class that can only contain static methods.

• A type of variable used for method overloading.

How are interfaces different from abstract classes?

• Interfaces can have constructors, while abstract classes cannot.

• Abstract classes can contain both abstract and concrete methods, while interfaces can only contain abstract methods.

• Interfaces cannot be extended by other interfaces, while abstract classes can.

• Abstract classes can have instance variables, while interfaces cannot.

Which keyword is used to declare an interface in Java?

• interface

• class

• abstract

• implements

How can a class in Java realize an interface?

• By using the extends keyword.

• By using the implements keyword followed by the interface name.

• By directly inheriting from the interface class.

• By using the implements keyword followed by the class name.

Which of the following is true about interfaces in Java?

• A class can implement multiple interfaces.

• An interface can implement another interface.

• An interface can extend a class.

What happens if a class in Java fails to implement all the methods of an interface it claims to implement?

• It results in a syntax error during compilation.

• It automatically inherits the default implementations of those methods.

• It compiles successfully, but throws a runtime exception.

• It has no effect on compilation or runtime behavior.

Which of the following statements about interface variables is true?

• Interface variables are implicitly final and static.

• Interface variables can be reassigned new values after declaration.

• Interface variables can only be accessed through static methods.

• Interface variables can have different access modifiers depending on the implementing class.

Can an interface in Java contain fields (variables)?

• Yes, but only if they are declared as static final.

• Yes, but only if they are declared as private.

• No, interfaces cannot contain fields.

• No, fields are not allowed in any interface.

How many interfaces can a class implement in Java?

• Only one

• Two

• Three

• Unlimited

Which of the following statements about interface inheritance is true?

• An interface can inherit from multiple classes.

• A class can inherit from multiple interfaces.

• An interface cannot inherit from another interface.

• An interface can inherit from both classes and other interfaces.