What are Java interfaces and how do they work?

What are Java interfaces and how do they work?

Java interfaces are abstract types that allow you to define methods that must be implemented by classes. They enable multiple inheritance and provide a way to achieve abstraction.

Can you give me an example of a Java interface?

Sure! Here's a simple example:

interface Animal {
    void makeSound();
}

class Dog implements Animal {
    public void makeSound() {
        System.out.println("Woof!");
    }
}

In this example, Animal is an interface with a method makeSound, and Dog implements this interface.

What is the difference between an interface and an abstract class?

The main difference is that an interface can only contain method signatures and constants, while an abstract class can have method implementations and instance variables. A class can implement multiple interfaces but can only extend one abstract class.

When should I use an interface instead of an abstract class?

Use an interface when you want to define a contract that multiple classes can implement, especially when those classes are not related. Use an abstract class when you want to share code among closely related classes.