final keyword in java is used to make any class or a method or a field as unchangeable. You can’t extend a final class, you can’t
override a final method and you can’t change the value of a final field. final keyword is used to achieve high level of security
A final class is very useful when you want a high level of security in your application. If you don’t want inheritance of a
particular class, due to security reasons, then you can declare that class as a final..