code: protected Message lookupMessage(String queueName)  {
          checkStarted();
  
          try(Session session = consumerConnection.createSession()) {
              Queue queue = (Queue) jmsServer.lookup(QUEUE_NAMESPACE + queueName);
              Enumeration messages = session.createBrowser(queue).getEnumeration();
              return (Message) messages.nextElement();
          }catch (NoSuchElementException e){
              return null;
          }
          catch (Exception e) {
              throw new AsyncException("Lookup failed", e);
          }
      }
docs: This method exists for testing