synchronized (deliveryLock) { boolean removed = deliveries.remove(d);  if (trace) { log.trace(this + " removed " + d + " from memory:" + removed); } }
if (trace) { log.trace(this + " removed " + d + " from memory:" + removed); }
   protected void acknowledgeInMemory(Delivery d) throws Throwable   {            if (d == null)      {         throw new IllegalArgumentException("Can't acknowledge a null delivery");      }            synchronized (deliveryLock)      {               boolean removed = deliveries.remove(d);                  if (trace) { log.trace(this + " removed " + d + " from memory:" + removed); }       }   }