Interfaces in Java - Multiple Inheritance

Interfaces

An interface is a completely "abstract class" that is used to group related methods with empty bodies.

Key Points:

• Use interface keyword.
• Methods are by default abstract and public.
• Attributes are by default public, static, and final.
• A class implements an interface.

interface Animal {
  public void animalSound(); // interface method (does not have a body)
  public void sleep(); // interface method (does not have a body)
}
class Pig implements Animal {
  public void animalSound() {
    System.out.println("The pig says: wee wee");
  }
  public void sleep() {
    System.out.println("Zzz");
  }
}