if (log.isTraceEnabled()) { log.trace("stored " + m + " on disk"); }
if (trace) { log.trace("stored " + m + " on disk"); }
   public MessageReference reference(Message m)   {      MessageReference ref = super.reference(m);            if (log.isTraceEnabled()) { log.trace(this + " referencing " + m); }      if (m.isReliable())      {                  try         {            storeMessage(m);         }         catch (Exception e)         {            log.error("Failed to store message", e);         }                  if (log.isTraceEnabled()) { log.trace("stored " + m + " on disk"); }               }      return ref;   }