code: protected ConnectionListener removeConnectionListener(boolean free, Collection<ConnectionListener> listeners)
     {
        if (free)
        {
           for (ConnectionListener cl : listeners)
           {
              if (cl.changeState(FREE, IN_USE))
                 return cl;
           }
        }
        else
        {
           for (ConnectionListener cl : listeners)
           {
              if (cl.getState() == IN_USE)
                 return cl;
           }
        }
  
        return null;
     }
docs: Remove a free ConnectionListener instance
  @param free True if FREE, false if IN_USE
  @param listeners The listeners
  @return The ConnectionListener, or <code>null</code>