What are instanceof Operator (used for Type Comparison) in java

instanceof Operator  (used for Type Comparison)
  • instanceof operator compares an object to a specified type.
  • instanceof operator test if an object is an instance of a
    • class or
    • subclass or.
    • Any implemented interface.
  • By default all reference variable of all classes/interface are instanceof Java.lang.Object class
  • null is instanceof nothing.


Program 6 to demonstrate instanceof operator
class SuperClass {}
class SubClass extends SuperClass{}
/** JavaMadeSoEasy.com */
public class InstanceofTest {
   public static void main(String[] args) {
       SuperClass sup = new SuperClass();
       SuperClass sub = new SubClass();
       System.out.println("------------------SubClass instanceOf---");
      
       System.out.println("SuperClass instanceof SuperClass - "
        + (sup instanceof SuperClass));
       System.out.println("SuperClass instanceof SubClass - "
        + (sup instanceof SubClass));
       System.out.println("SuperClass instanceof java.lang.Object - "
        + (sup instanceof java.lang.Object));
       System.out.println("\n------------------SubClass instanceOf---");
      
       System.out.println("SubClass instanceof SuperClass - "
        + (sub instanceof SuperClass));
       System.out.println("SubClass instanceof SubClass - "
        + (sub instanceof SubClass));
       System.out.println("SubClass instanceof java.lang.Object - "
        + (sub instanceof java.lang.Object));
   }
}
/*OUTPUT
------------------SubClass instanceOf---
SuperClass instanceof SuperClass - true
SuperClass instanceof SubClass - false
SuperClass instanceof java.lang.Object - true
------------------SuperClass instanceOf---
SubClass instanceof SuperClass - true
SubClass instanceof SubClass - true
SubClass instanceof java.lang.Object - true
*/

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