What is Final Keyword?

In Java, the final keyword is used to restrict changes and make code more secure and predictable.
It can be applied to variables, methods, and classes to prevent modification, overriding, or inheritance.
This helps in creating constant values, stable methods, and immutable classes.

• Final variable: cannot be changed once assigned

Example

class Geeks {
    public static void main(String[] args) {
        final int i;
        i = 20;
        System.out.println(i);
    }
}

• Final method: cannot be overridden

Example

class A {
    final void m1() {
        System.out.println("Final method");
    }
}

class B extends A {
    void m1() { } // compile-time error
}

• Final class: cannot be inherited.

Example

final class A {
    // fields and methods
}

// Illegal
class B extends A { }