IoT using Eclipse Paho for Java, Mosquitto MQTT and ESP8266

In this video, I build a simple Internet-of-Things example using the following tools: - Microsoft Windows 10 PC - Eclipse Mosquitto free MQTT Message Broker for Windows - Eclipse Paho Java library - An ESP8266 microcontreller with WiFi - ESPEasy firmware for ESP8266 - Espressif memory flashing application for ESP8266 - Node-Red Here is the Java code: File "App.java": package application.IoT_Application; import java.util.UUID; import org.eclipse.paho.client.mqttv3.IMqttToken; import org.eclipse.paho.client.mqttv3.MqttAsyncClient; import org.eclipse.paho.client.mqttv3.MqttException; public class App { public static MqttAsyncClient myClient; public static void main( String[] args ) throws MqttException { myClient = new MqttAsyncClient("tcp://192.168.1.70:1883", UUID.randomUUID().toString()); MyCallback myCallback = new MyCallback(); myClient.setCallback(myCallback); IMqttToken token = myClient.connect(); token.waitForCompletion(); myClient.subscribe("/ESP-01_MQTT_client1/Input_Switch/On_Off_Value = ", 0); } } File "MyCallback.java": package application.IoT_Application; import org.eclipse.paho.client.mqttv3.IMqttDeliveryToken; import org.eclipse.paho.client.mqttv3.MqttCallback; import org.eclipse.paho.client.mqttv3.MqttMessage; public class MyCallback implements MqttCallback { public void connectionLost(Throwable arg0) { // TODO Auto-generated method stub } public void deliveryComplete(IMqttDeliveryToken arg0) { // TODO Auto-generated method stub } public void messageArrived(String topic, MqttMessage message) throws Exception { App.myClient.publish("/ESP-01_MQTT_client2/Output_Switch/On_Off_Value = ", message.getPayload(), 0, false); } }