title: Push server implementation technology?
body: <p>I'm planning to develop a solution which uses push functionality. There will be a server and mobile device client application. </p>
  
  <p>I need to know how to push messages in to the client from the server. That is my client application is passively waiting until a messages comes from the server. </p>
  
  <p>What is the technology behind pushing the messages from the server. </p>
  
  <p>Clients are in the form of  Android,J2me,BB,iphone etc</p>