Overloading

[shruti patel]

what is the purpose of method overriding in Java where we are completely re-defining a inherited method instead why can't we create a new method and define.If the question is very silly please excuse me and do reply

[Campbell Ritchie]

No, it isn't a silly question.

An overridden method allows you to use the same invocation as in the superclass and receive a different result.

[Sagar Rohankar]

Consider an Interface , When we implement an interface we have to override the abstract methods , because thats the contract we need to fulfill in order to successfully implement the interface !

Now I`m not much experienced in java , this what I got from my 1 year of experience as per need of overriding !!

1. sometimes a base class defined a very basic operation , and the code which extends it must have to implement the more advance code for that method , like If we consider an base class 'Car', which got start() method

 class Car
{public void start()
{
     System.out.println("Staring..");
}
}   

and when we want the class which IS a Car with more specialized functionality , lets say Ferrari ,

 class Car
{public void start() // override
{
     super.start();
     System.out.println("Zoommm..");
 
}
}   

Now If we define a new method for start(), then What ll be the use of that Car#start() code , We must concentrate the re usability of the code .

[Thanks for correcting me , Campbell ]
[ August 12, 2008: Message edited by: Sagar Rohankar ]

[Campbell Ritchie]

The Car and Ferrari example shows overriding nicely, but it should read super.start() not super().