A note of Overriding.

Overriding.java

class Animal {
  public String talk() {
    return "Hi";
  }
}

class Dog extends Animal {
  public String talk() {
    return "Woof!";
  }
}

static void main(String[] args) {
  Animal a = new Dog();
  a.talk(); // return "Woof!" not "hi"
}