code: public void stop()
      {
          // Invalidate all sessions to cause unbind events
          ArrayList sessions = new ArrayList(_sessions.values());
          for (Iterator i = sessions.iterator(); i.hasNext(); )
          {
              Session session = (Session)i.next();
              session.invalidate();
          }
          _sessions.clear();
          
          // stop the scavenger
          SessionScavenger scavenger = _scavenger;
          _scavenger=null;
          if (scavenger!=null)
              scavenger.interrupt();
      }
docs: /* ------------------------------------------------------------