How instanceof will work on an interface

Question

instanceof can be used to test if an object is a direct or descended instance of a given class. instanceof can also be used with interfaces even though interfaces can't be instantiated like classes. Can anyone explain how instanceof works?

Answer 1

First of all, we can store instances of classes that implements a particular interface in an interface reference variable like this.

package com.test;  public class Test implements Testable {      public static void main(String[] args) {          Testable testable = new Test();          // OR          Test test = new Test();          if (testeable instanceof Testable)             System.out.println("instanceof succeeded");         if (test instanceof Testable)             System.out.println("instanceof succeeded");     } }  interface Testable {  } 

ie, any runtime instance that implements a particular interface will pass the instanceof test

EDIT

and the output

instanceof succeeded instanceof succeeded 

@RohitJain

You can create instances of interfaces by using anonymous inner classes like this

Runnable runnable = new Runnable() {          public void run() {         System.out.println("inside run");     } }; 

and you test the instance is of type interface, using instanceof operator like this

System.out.println(runnable instanceof Runnable); 

and the result is 'true'

Answer 2

object instanceof object_interface will yield true.