What happens if you declare a class as final in Java?

If you declare a class as final in Java:

1. Cannot be Extended: No other class can inherit from it, ensuring the class’s behavior cannot be altered through inheritance.

2. Security and Integrity: Useful for creating immutable or secure classes, like String.

3. Optimization: JVM can apply certain performance optimizations knowing the class won’t be extended.

In short: A final class is a “sealed” class to protect its implementation and improve reliability.