public static void main()

in mqtt-example/src/main/java/org/apache/rocketmq/mqtt/example/MqttWillRetainConsumer.java [35:82]
44 lines of code
4 McCabe index (conditional complexity)

    public static void main(String[] args) throws MqttException, NoSuchAlgorithmException, InvalidKeyException {
        String brokerUrl = "tcp://" + System.getenv("host") + ":1883";
        String firstTopic = System.getenv("topic");
        MemoryPersistence memoryPersistence = new MemoryPersistence();
        String recvClientId = "recv02";
        MqttConnectOptions mqttConnectOptions = buildMqttConnectOptions(recvClientId);
        MqttClient mqttClient = new MqttClient(brokerUrl, recvClientId, memoryPersistence);
        mqttClient.setTimeToWait(5000L);
        mqttClient.setCallback(new MqttCallbackExtended() {
            @Override
            public void connectComplete(boolean reconnect, String serverURI) {
                System.out.println(recvClientId + " connect success to " + serverURI);
                try {
                    final String topicFilter[] = {firstTopic + "/retainTopicR",firstTopic + "/retainTopic/+", firstTopic + "/willTopic1",};
                    final int[] qos = {1, 1, 1};
                    mqttClient.subscribe(topicFilter, qos);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }

            @Override
            public void connectionLost(Throwable throwable) {
                throwable.printStackTrace();
            }

            @Override
            public void messageArrived(String topic, MqttMessage mqttMessage) throws Exception {
                try {
                    String payload = new String(mqttMessage.getPayload());
                    System.out.println(now() + "receive:" + topic + "," + payload);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }

            @Override
            public void deliveryComplete(IMqttDeliveryToken iMqttDeliveryToken) {
            }
        });

        try {
            mqttClient.connect(mqttConnectOptions);
        } catch (Exception e) {
            e.printStackTrace();
            System.out.println("connect fail");
        }
    }