Java Interfaces

What is an abstract interface in Java?

• An abstract interface in Java is a type of method that can have default methods.

• An abstract interface in Java is a type of interface that can have abstract methods and default methods.

• An abstract interface in Java is a type of class that can have abstract methods.

• An abstract interface in Java is a type of interface that cannot have any methods.

Can an interface in Java have method implementations?

• Only in certain cases

• Sometimes

• Yes

• No

How do you define an interface in Java?

• An interface in Java can only contain constants and static methods.

• An interface in Java is a concrete class with method implementations.

• An interface in Java is used for defining data structures.

• An interface in Java is a reference type that can contain constants, method signatures, default methods, static methods, and nested types, but no method bodies.

Can a class implement multiple interfaces in Java?

• Yes

• Rarely

• Sometimes

• No

What is the purpose of using interfaces in Java?

• Interfaces in Java are used to create multiple instances of a class.

• Interfaces in Java define a contract for classes to implement.

• Interfaces in Java are only used for documentation purposes.

• Interfaces in Java slow down the performance of the program.

Explain the concept of multiple inheritance in Java interfaces.

• Multiple inheritance in Java interfaces means that an interface can implement multiple classes.

• Java interfaces support multiple inheritance by allowing classes to implement multiple interfaces.

• In Java interfaces, multiple inheritance is achieved by allowing interfaces to extend multiple interfaces.

• In Java interfaces, multiple inheritance is achieved by allowing classes to extend multiple classes.

What is the difference between abstract classes and interfaces in Java?

• Abstract classes can have method implementations and instance variables, while interfaces cannot have method implementations and only contain method signatures.

• Abstract classes can be instantiated directly, while interfaces cannot

• Interfaces can have instance variables, while abstract classes cannot

• Interfaces can have method implementations, while abstract classes cannot

How do interfaces help achieve abstraction in Java?

• Interfaces are only used for single inheritance in Java.

• Interfaces define a contract for classes to follow without revealing implementation details.

• Interfaces make classes more complex and harder to understand.

• Interfaces are used to directly access class attributes.

Can you create an object of an interface in Java?

• Yes

• No

• Sometimes

• Only in certain cases

Predict the output of the given program

• method1

• Compilation Error