code: public final AbstractItem findOldestItem() throws MessageStoreException
      {
          AbstractItem item = null;
          AbstractItemLink oldestLink = null;
          long oldestPositionSoFar = Long.MAX_VALUE;
          for (int priority = Priorities.LOWEST_PRIORITY; priority <= Priorities.HIGHEST_PRIORITY; priority++)
          {
              LinkedList list = _prioritySublists[priority];
              if (null != list)
              {
                  AbstractItemLink link = (AbstractItemLink) list.getHead();
                  if (null != link)
                  {
                      final long pos = link.getPosition();
                      if (pos < oldestPositionSoFar)
                      {
                          oldestPositionSoFar = pos;
                          oldestLink = link;
                      }
                  }
              }
          }
          if (null != oldestLink)
          {
              item = oldestLink.getItem();
          }
          return item;
      }
docs: /*
  (non-Javadoc)
  
  @see com.ibm.ws.sib.msgstore.ItemCollection#findOldestItem()