title: How to easily implement "who is online" in Grails or Java Application?
body: <p>I am building a community website in grails (using Apache Shiro for security and authentication system) and I would like to implement the feature "who is online?". </p>
  
  <p>This url <a href="http://cksource.com/forums/viewonline.php" rel="noreferrer">http://cksource.com/forums/viewonline.php</a> (see snapshot below if you do not have acess to this Url) gives an example of what I would like to achieve.</p>
  
  <p>How can I do that in the most simple way? Is there any existing solution in Grails or in Java ?</p>
  
  <p>Thank you.</p>
  
  <p>Snapshot : <a href="http://www.freeimagehosting.net/uploads/th.2de8468a86.png" rel="noreferrer">Snapshot of Who is online page http://www.freeimagehosting.net/uploads/th.2de8468a86.png</a> or see here : <a href="http://www.freeimagehosting.net/image.php?2de8468a86.png" rel="noreferrer">http://www.freeimagehosting.net/image.php?2de8468a86.png</a></p>