if (trace) { log.trace(this + " adding " + ref + " non-transactionally"); }
   protected boolean addReferenceInMemory(MessageReference ref) throws Throwable   {      if (trace) { log.trace(this + " adding " + ref + " non-transactionally"); }      if (ref.isReliable() && !acceptReliableMessages)      {         throw new IllegalStateException("Reliable reference " + ref +                                         " cannot be added to non-recoverable state");      }      if (trace) { log.trace(this + " added " + ref + " in memory"); }             ref.setOrdering(getNextReferenceOrdering());            boolean first = messageRefs.addLast(ref, ref.getPriority());             if (messageRefs.size() == fullSize)      {                     //We are full in memory - go into paging mode         paging = true;      }                  return first;       }