Howdy, Helen!
So, in the real-exam, are we required to make client server talk in 2 ways?
No. This is not required. I myself implemented the client's updating in a piggyback style. So, for instance, let's say that client 1 is looking at the window, and all records are available. Client 2 updates record 2 and client 3 updates record 3. Client's 1 window is not updated. Then, client 1 updates record 1. When he does so, then his window is updated, showing that records 1, 2 and 3 where udpated. So the client's window is only updated when he/she sends some data to the server.
Cheers, Roberto Perillo
SCJP, SCWCD, SCJD, SCBCD