code: protected Session getConsumerSession() throws JMSException {
          if (consumerSession == null) {
              synchronized (this) {
                  if (consumerSession == null) {
                      consumerSession = createSession(Session.AUTO_ACKNOWLEDGE);
                  }
              }
          }
          return consumerSession;
      }
docs: Get the {@link Session} dedicated for consuming messages.
  
  @return
  @throws JMSException