final Keyword

There are three uses of final:

(1)           To make the variable constant

The variable declared as a final cannot be changed. It is common coding convention to choose all uppercase identifiers for final variables.

final int ADD=1;

final string ST1=” This is Java “;

(2)           To prevent overriding of method

The method declared as a final cannot be overridden.

Ex,

class A

{

     final void add ()

     {

               System.out.println (“This is Final Method“);

     }

}

class B extends A

{

     void add ()             //error b’coz add is Final

     {

    

     }

}

(3)            To prevent Inheritance

The class declared as a final cannot be inherited means it has no derivatives. It is a standalone class.

Ex,

final class A

  {

           

  }

class B extends A      // error can’t be inherited

{

 

}

Posted by:Ruchita Pandya