Java Programming: simple Polymorphic programming

public class Dog extends Animal{public void noise(){System.out.println("Ruff");}}

public class Fish extends Animal{public void noise(){System.out.println("Gree");}}

public class Animal {public void noise(){System.out.println("Animal dint amke noise");}}

public class Main {public static void main(String[] args){Animal[] thelist = new Animal[2];Dog d = new Dog();Fish f = new Fish();thelist[0] = d;thelist[1] = f;for(Animal x: thelist){x.noise();}}}

the result is ；

Ruff
Gree