instanceof

In Java, the "instanceof" operator is used to test whether an object is an instance of a particular class or interface. It returns "true" if the object is an instance of the specified type or one of its subtypes, otherwise it returns "false". The "instanceof" operator is primarily used for type checking and type casting in Java.

Here's a basic example demonstrating the usage of the "instanceof" operator.

class Animal {
    // animal class definition
}

class Dog extends Animal {
    // dog class definition
}

class Cat extends Animal {
    // cat class definition
}

public class Main {
    public static void main(String[] args) {
        Animal animal1 = new Dog(); // create a Dog object and assign it to an Animal reference
        Animal animal2 = new Cat(); // create a Cat object and assign it to an Animal reference

        // test if animal1 is an instance of Dog
        if (animal1 instanceof Dog) {
            System.out.println("animal1 is a Dog");
        } else {
            System.out.println("animal1 is not a Dog");
        }

        // test if animal2 is an instance of Dog
        if (animal2 instanceof Dog) {
            System.out.println("animal2 is a Dog");
        } else {
            System.out.println("animal2 is not a Dog");
        }

        // test if animal1 is an instance of Animal
        if (animal1 instanceof Animal) {
            System.out.println("animal1 is an Animal");
        } else {
            System.out.println("animal1 is not an Animal");
        }

        // test if animal1 is an instance of Cat
        if (animal1 instanceof Cat) {
            System.out.println("animal1 is a Cat");
        } else {
            System.out.println("animal1 is not a Cat");
        }
    }
}

Output:

animal1 is a Dog
animal2 is not a Dog
animal1 is an Animal
animal1 is not a Cat

In this example:

- We have a class hierarchy with "Animal" as the superclass and "Dog" and "Cat" as subclasses.

- We create instances of "Dog" and "Cat" and assign them to variables of type "Animal".

- We use the "instanceof" operator to test whether each object is an instance of a specific class ("Dog", "Cat") or interface ("Animal").

- Based on the results of the "instanceof" checks, we print appropriate messages indicating the type of each object.