imanasardar

 Profile Answers by imanasardar 

• Sep 23rd, 2010

 

superclass classname=new subclass()

manoj.muthavarapu

 Profile Answers by manoj.muthavarapu 

• Oct 27th, 2010

 

We extend a class to provide a more specialized behavior for it in the subclass. For example, consider the class "Vehicle" and imagine a subclass "Bus". All vehicle objects are capable of moving. Bus is a specific type of a vehicle which is quite big and can carry a lot of passengers. A vehicle object cannot assume the functionalities of a bus. For such a case, where we want to perform general functions (like moving) over a very broad collection of classes (like vehicles) even when we have specific objects (like buses), we can use downcasting. It is a way of limiting your capabilities to make sure that all your subclass objects are still capable of doing them.

muralidhar.9e

 Profile Answers by muralidhar.9e 

• Oct 29th, 2010

 

Downcasting means using the super class object into the subclass.And we are cating to our sub class object.
Like let's assume super and sub classes

class BaseClass{
      -------
      -------
      -------

}

class SubClass extends BaseClass{
    ------------
    -----------
  SubClass sc=(SubClass)new BaseClass();
}

Here we are using the super class reference in the type of subclass object.This is called DownCasting.