MQTT Sender/Consumer

MQTTConsumer.java

import org.eclipse.paho.client.mqttv3.*;
import org.eclipse.paho.client.mqttv3.persist.MemoryPersistence;

import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;

public class MQTTConsumer {
    public static void main(String[] args) {

        String topic = "sah/+/#";
        String broker = "tcp://90.183.120.37:1883";
        String clientId = "JavaSample1";
        MemoryPersistence persistence = new MemoryPersistence();

        try {
            MqttClient sampleClient = new MqttClient(broker, clientId, persistence);
            MqttConnectOptions connOpts = new MqttConnectOptions();
            connOpts.setCleanSession(true);
            sampleClient.connect(connOpts);

            sampleClient.subscribe(topic);
            sampleClient.setCallback(new MqttCallback() {
                public void connectionLost(Throwable throwable) {
                    throwable.printStackTrace();
                }

                public void messageArrived(String topic, MqttMessage mqttMessage) throws Exception {
                    System.out.println("Topic : " + topic + " Message : " + mqttMessage);
                }

                public void deliveryComplete(IMqttDeliveryToken iMqttDeliveryToken) {
                    System.out.println("Delivery complete : " + iMqttDeliveryToken);
                }
            });

            new CountDownLatch(1).await(100, TimeUnit.SECONDS);
            sampleClient.disconnect();            
        } catch (MqttException | InterruptedException e) {
            e.printStackTrace();
        }
    }
}

MQTTSender.java

import org.eclipse.paho.client.mqttv3.MqttClient;
import org.eclipse.paho.client.mqttv3.MqttConnectOptions;
import org.eclipse.paho.client.mqttv3.MqttException;
import org.eclipse.paho.client.mqttv3.MqttMessage;
import org.eclipse.paho.client.mqttv3.persist.MemoryPersistence;

import java.nio.charset.Charset;

public class MQTTSender {
    public static void main(String[] args) {

        String topic = "sah/to/HGW-3D00534148475555FBKL00100000587/api/Devices/Device/ZWAVE_13/off";
        String broker = "tcp://90.183.120.37:1883";
        String clientId = "JavaSample";
        MemoryPersistence persistence = new MemoryPersistence();

        try {
            MqttClient sampleClient = new MqttClient(broker, clientId, persistence);
            MqttConnectOptions connOpts = new MqttConnectOptions();
            connOpts.setCleanSession(true);
            sampleClient.connect(connOpts);

            Charset utf8 = Charset.forName("UTF-8");
            MqttMessage message = new MqttMessage( "{\"From\":\"me\", \"CallId\":321, \"Arguments\":{} }".getBytes(utf8));
            message.setQos(0);
            sampleClient.publish(topic, message);
            sampleClient.disconnect();            
        } catch (MqttException e) {
            e.printStackTrace();
        }
    }
}