docs: static void export(String path, String queueName, DbConn cnx) throws JqmXmlException
      {
          // Argument tests
          if (queueName == null)
          {
              throw new IllegalArgumentException("queue name cannot be null");
          }
          if (cnx == null)
          {
              throw new IllegalArgumentException("database connection cannot be null");
          }
          Queue q = CommonXml.findQueue(queueName, cnx);
          if (q == null)
          {
              throw new IllegalArgumentException("there is no queue named " + queueName);
          }
  
          List<Queue> l = new ArrayList<>();
          l.add(q);
          export(path, l, cnx);
      }