// Obtain the client.
   MQClient mqClient = new MQClient(endpoint, accessKey, secretKey);

   // Obtain the consumer of the topic.  
   MQConsumer consumer = mqClient.getConsumer(namespace, topicName, groupName, "TAG");

do {
    List<Message> messages = null;

    try {
        // Consume messages in order through long round-robin scheduling. The messages obtained may be from different partitions, but the order of messages within a single partition is guaranteed.
        // For ordered consumption, if any message within a partition is not successfully acknowledged, messages from the partition will be consumed again.
        // For a given partition, consumption of the next batch proceeds only after all messages in the current batch are successfully acknowledged.
        // If your business is sensitive to consumption delays, it is highly recommended to pull messages concurrently using multiple threads.
        messages = consumer.consumeMessageOrderly(
                Integer.parseInt(batchSize),
                Integer.parseInt(waitSeconds)
        );
    } catch (Throwable e) {
        e.printStackTrace();
    }
    if (messages == null || messages.isEmpty()) {
        System.out.println(Thread.currentThread().getName() + ": no new message, continue!");
        continue;
    }

    for (Message message : messages) {
        System.out.println("Receive message: " + message);
    }

    {
        List<String> handles = new ArrayList<String>();
        for (Message message : messages) {
            handles.add(message.getReceiptHandle());
        }

        try {
            consumer.ackMessage(handles);
        } catch (Throwable e) {
            if (e instanceof AckMessageException) {
                AckMessageException errors = (AckMessageException) e;
                System.out.println("Ack message fail, requestId is:" + errors.getRequestId() + ", fail handles:");
                if (errors.getErrorMessages() != null) {
                    for (String errorHandle :errors.getErrorMessages().keySet()) {
                        System.out.println("Handle:" + errorHandle + ", ErrorCode:" + errors.getErrorMessages().get(errorHandle).getErrorCode()
                                + ", ErrorMsg:" + errors.getErrorMessages().get(errorHandle).getErrorMessage());
                    }
                }
                continue;
            }
            e.printStackTrace();
        }
    }
} while (true);