Casting of Objects

[Pallavi Chakraborty]

Hey everybody,
Here is a code :

class Base {}
class Sub extends Base {}
class Sub2 extends Base {}
public class CEx
{    
   public static void main(String argv[])
   {
      Base b=new Base();
      Sub s=(Sub) b;    
   }
}

1) Compile and run without error
2) Compile time Exception
3) Runtime Exception
The answer given is a - I thought Sub s = (Sub) b; is a valis narrowing cast.
What do you say ?
Pallavi
Edited by Corey McGlone: Broke up long line in code section to preserve page formatting.
[ April 04, 2003: Message edited by: Corey McGlone ]

[Corey McGlone]

This code gives a ClassCastException at runtime. You can not cast a parent class into a child class.

[mohamed hamdy]

i can add that if you change the code of constructing object as follows:
Base b=new Sub();
it'll compile and run successifully

[Monisha Talwar]

Pallavi,
I think the given answer is wrong. It compiles fine and then throw a run time error -ClassCastException.
You are right, the answer should be C or 3 : Runtime Exception