Q:

Java event oriented Socket library

I am looking for any good Socket library with events for Java.  Mainly it should be used for client development.  Server side is already finished (in other language). 
Thank you very much. 

A:

It seems that the best one is jBoss Netty

The Netty project is an effort to provide an asynchronous event-driven
  network application framework and tools for rapid development of
  maintainable high performance & high scalability protocol servers &
  clients.