title: JAVA push from server to clients
body: <p>I would like to have the clients query each other through the server without delay ( = no polling interval ).</p>
  
  <p>Example: Server S, clients A and B</p>
  
  <p>Client A wants to request Client B.
  Client A will make a request to the server S, no problem there.
  Then Server S needs to be able to request Client B but how to do that without polling?</p>
  
  <p>All the node.js/APE (for PHP) technos are designed for the web, however I don't use a web server for that. Does Java has something close to a push technology/framework that is not web?</p>
  
  <p>I would really prefer a solution that doesn't require each client to use their own reserved port (I don't want to end up with 1 WebService per client for example)</p>
  
  <p>Note: all the clients are on the same machine.</p>