METHOD OVERRIDING

    In situations where a method in a subclass has the same name and type signature as a method in its superclass, then the method in the subclass is said to override the method in the superclass.

    When an overridden method is called from within a subclass, it will always refer to the subclass version of the method. The version of the method defined by the superclass will be hidden.

     Ex:class Base

{

 void show()

 {

  System.out.println("Base class show method is called");

 }

}

class Derive extends Base

{

 void show() //show method is overridden

 {

  System.out.println("Derive class show method is called");

 }

}

class Override

{

public static void main(String args[])

 {

  Derive s=new Derive();

  s.show();

 }

}

Output:Derive class show method is called

    Dynamic Method Dispatch:

o   Dynamic Method Dispatch is a mechanism by which a call to an overridden method is resolved at run time, rather than compile time.

o   Dynamic Method Dispatch is important because this is how java implements run time polymorphism.

o   When an overridden method is called through a superclass reference, Java determineswhich version of that method to execute based upon the type of the object being referred to at the time of call occurs.

    Ex: class Base

{

 void show()

 {

  System.out.println("Base class show method is called");

 }

}

class Derive1extends Base

{

 void show() //show method is overridden

 {

  System.out.println("Derive class 1 show method is called");

 }

}

class Override

{

public static void main(String args[])

 {

  Base b=new Base();

  Derive1 d1=new Derive1();

Base r;

  r=b;

  r.show();

r=d1;

  r.show();

 }

}

Output:Base class show method is called

          Derive class 1 show method is called