For what situations and purposes is the final modifier used in programming?

The final modifier in Java is used to restrict the modification or overriding of entities:

• For classes: a class declared as final cannot be subclassed. This is useful when you want to prevent extension of a class.

• For methods: a method declared as final cannot be overridden in subclasses. This guarantees that the method's implementation remains unchanged.

• For variables: a variable declared as final becomes a constant — its value can only be assigned once.

Example:

final class ImmutableClass {
    final int value;

    public ImmutableClass(int value) {
        this.value = value;
    }

    public final void display() {
        System.out.println("Value: " + value);
    }
}

// Attempting to inherit or override methods of this class will cause a compile error.

Using final helps improve code safety, prevent unwanted changes, and enhance readability.