Socket Programing in J2ME - Confused with Sun Sample Code

Question

Hai Everybody,
I have confused with sample code provided by Sun Inc , for the demo of socket programming in J2ME. I found the code in the API specification of J2ME. The code look like :-
// Create the server listening socket for port 1234
ServerSocketConnection scn =(ServerSocketConnection) Connector.open("socket://:1234");
where Connector.open() method return an interface Connection which is the base interface of ServerSocketConnection. I have confused with this line , is it is possible to cast base class object to the derived class object?
Plese help me in this regards
Thanks in advance
Sulfikkar

Answer 1

There is nothing to be confused about. The Connector factory creates an implementation of one of the extentions of the Connection interface and returns it.
For a serversocket "socket://<port>" it will return an implementation of the ServerSocketConnection interface. You don't need to know what the implementation looks like. You'll only need to cast the Connection to a ServerSocketConnection .