Interface in Java

Introduction An interface in Java is used to achieve abstraction and multiple inheritance. It defines what a class should do, but not how it should do it. In simple words: Interface is a contract that a class must follow. What is an Interface? An interface is declared using the keyword interface It contains abstract methods (by default) A class uses implements keyword to implement an interface Object cannot be created for an interface Why Use Interface in Java? To achieve abstraction To support multiple inheritance To achieve loose coupling To define common behavior for unrelated classes Syntax: interface InterfaceName { void method1(); void method2(); } After Java 8, interfaces can have default methods. If a class implements two interfaces that contain default methods with the same signature, the class must override the method and explicitly specify which interface method to call using InterfaceName.super.methodName(); Important Rules of Interface All methods are public and abstract b