🎯 1. What is final Keyword?

final means “cannot be changed further.”

You use final when you want permanent, unmodifiable, or fixed values/structures in your program.

Depending on what you apply it to:

• final variable → value cannot change
• final method → cannot be overridden
• final class → cannot be inherited

🧱 2. final Variable (Constant)

✔ Used for constant values

Syntax:

final int MAX_SPEED = 120;

This value cannot be changed:

MAX_SPEED = 150; // ❌ ERROR

Important:

• Must be initialized once
• Often written in UPPERCASE
• Used to define constants:
  • PI
  • MAX_USERS
  • APP_VERSION

⭐ 3. final Method (No Overriding)