Polymorphism

Polymorphism allows objects to take many forms. It includes method overriding and overloading.

class Animal {
  void speak() {
    System.out.println("Animal speaks");
  }
}

class Cat extends Animal {
  void speak() {
    System.out.println("Cat meows");
  }
}

At runtime, the JVM decides which method to call depending on the object type.