Java APIs

Hi

im building a client/server program that the server is writen in J2SE and the client in J2ME ( mobile ).

The client sould send request to the server - then the server will process the request and start sening data ( continues streaming data )to the client till it get new request , and start sending data according to the new new request .
my question is how i sould design the client reader and writer to handle data streeming , should i have 2 threds for that? or it's posible to do it in one

i'll be glad to get reference for that ( never mind for what platform i wana learn the consept how to design )

Thanks