FINAL Keyword

Some basic uses of  Keyword final are:

    Using final to Define Variables: A varaible defined as final can never be changed. Final variables works like class variables and they do not take any space on individual object of the class.

Ex: class A {

final int size=100;

…….

}

    Using final to Prevent Overriding: To disallow a method from being overridden, specify final as a modifier at the start of its declaration.

Ex:class A

        {

           final void show()

           {

              System.out.println(“This is final method”);

           }

        }

class B extends A

{

void show() //ERROR: Can’t override.

            {

    System.out.println(“Not Possible”);

            }

         }

    Using final to Prevent Inheritance: To disallow a class from being inherited, specify final as a modifier at the start of its declaration.

Ex:final class A

        {

           void show()

           {

              System.out.println(“This is final method”);

           }

        }

class B extends A //ERROR: Can’t Inherit

{

void show()

            {

    System.out.println(“Not Possible”);

            }

         }