INTRODUCING final

In Java class can be declared as final using final keyword. If the final keyword is used in the class declaration the class becomes unable to be sub-classed. No any class can extend the final class i.e. features of a final class can't be inherited. Various classes of Java library are defined as final fro example java.lang.String, java.lang.System etc. If a final class contains the methods then these methods becomes final implicitly. In Java classes are declared as final for the security and efficiency reason. final makes the class immutable.