Question on Interface.

[SteveGuo]

> what? O_o
> let me explain, abstract class requires its successors to 
> implement all methods, but may have fields.
> class successors *always* do something, either their methods 
> has derived behavior or overridden ones. so does interface, if 
> you has class derived from interface then its successors may or 
> may not override its methods.

Thanks for replying, I think I need read more online-docs.