downcasting

[amit bhadre]

How to downcast a abstract class A to derived class D?

e.g:

abstract class A{
}
class derived {
derived d=new derived();
A a=new A();
d=(derived) a;
}

[Vijay Kiran]

You cannot instantiate object of abstract class using "new A();". If you want to have the abstract type from the derived you can directly use:

AbstractClass ab = new Derived();

[amit bhadre]

How to downcast a abstract class A to derived class D?

e.g:

abstract class A{
}
class derived {
derived d=new derived();

d=(derived) a;
}
how to convert a abstract class to a base class,is it possible?

[Jeff Albertson]

Originally posted by amit bhadre:
How to downcast a abstract class A to derived class D?

e.g:

abstract class A{
}
class derived {
derived d=new derived();

d=(derived) a;
}
how to convert a abstract class to a base class,is it possible?

For starters, you're going to have to learn a little bit of syntax:

public abstract class A{
}
 
public class Derived extends A {
public static void main(String[] args) {
Derived d = new Derived();
 A a = d;
 Derived d2 = (Derived) a;
}
 
}

For beginners, it helps to have a good book, like Head First Java, and to read some tutorials: http://java.sun.com/docs/books/tutorial/index.html

[amit bhadre]

Tank UUUUUUUUUU