🎯 1. What is Polymorphism?

Polymorphism = one action, many forms.

Same method name → different behavior depending on object type.

Example:

area() → circle, rectangle, square → each computes area differently.

Two types:

1. Compile-time polymorphism → Method Overloading
2. Runtime polymorphism → Method Overriding (today’s topic)

⭐ 2. Why Polymorphism Matters?

✔ Flexible code

✔ Cleaner architecture

✔ Extensible design

✔ Powerful abstraction

✔ Makes frameworks possible (Spring, Hibernate, JDBC)

Real use:

List list = new ArrayList();
list = new LinkedList(); // polymorphism

🧠 3. Runtime Polymorphism (Dynamic Dispatch)