title: How can I have list of all users logged in my web application
body: <p>I use <code>spring-mvc</code> and each use who logged in my web app i create a session variable <code>user</code> which is a object containing his <strong>id</strong>, name and some others info.</p>
  
  <pre><code>session.setAttribute("user", user);
  </code></pre>
  
  <p>What I want is to have a list of all users who are logged in my program.</p>
  
  <p>i want this list to check simultaneous log in because is must be just one access by account.</p>
  
  <p>ps : don't tell me to use <code>spring-security</code> because i want to work just with <code>MVC Interceptor</code> and <code>preHandle()</code></p>