Implementing null checks

components/device-mgt-iot-arduino/org.wso2.carbon.device.mgt.iot.arduino.controller.service.impl/src/main/java/org/wso2/carbon/device/mgt/iot/arduino/controller/service/impl/transport/ArduinoMQTTConnector.java

@@ -88,6 +88,7 @@ public class ArduinoMQTTConnector extends MQTTTransportHandler {
 
     @Override
     public void processIncomingMessage(MqttMessage message, String... messageParams) throws TransportHandlerException {
+        if(messageParams.length != 0) {
             String topic = messageParams[0];
             // owner and the deviceId are extracted from the MQTT topic to which the messgae was received.
             String ownerAndId = topic.replace(serverName + File.separator, "");
@@ -142,6 +143,7 @@ public class ArduinoMQTTConnector extends MQTTTransportHandler {
                 replyMessageList.add(message.toString());
             }
         }
+    }
 
     @Override
     public void disconnect() {

components/device-mgt-iot-digitaldisplay/org.wso2.carbon.device.mgt.iot.digitaldisplay.controller.api/src/main/java/org/wso2/carbon/device/mgt/iot/digitaldisplay/controller/api/util/DigitalDisplayMQTTConnector.java

@@ -65,6 +65,7 @@ public class DigitalDisplayMQTTConnector extends MQTTTransportHandler {
 
     @Override
     public void processIncomingMessage(MqttMessage message, String... messageParams) {
+        if(messageParams.length != 0) {
             String topic = messageParams[0];
             String ownerAndId = topic.replace("wso2" + File.separator + "iot" + File.separator, "");
             ownerAndId = ownerAndId.replace(File.separator + DigitalDisplayConstants.DEVICE_TYPE + File.separator, ":");
@@ -89,6 +90,7 @@ public class DigitalDisplayMQTTConnector extends MQTTTransportHandler {
                 DigitalDisplayWebSocketServerEndPoint.sendMessage(randomId, result);
             }
         }
+    }
 
     public void publishToDigitalDisplay(String topic, String payLoad, int qos, boolean retained)
             throws TransportHandlerException {

components/device-mgt-iot-raspberrypi/org.wso2.carbon.device.mgt.iot.raspberrypi.controller.service.impl/src/main/java/org/wso2/carbon/device/mgt/iot/raspberrypi/controller/service/impl/transport/RaspberryPiMQTTConnector.java

@@ -86,6 +86,7 @@ public class RaspberryPiMQTTConnector extends MQTTTransportHandler {
 
     @Override
     public void processIncomingMessage(MqttMessage message, String... messageParams) throws TransportHandlerException {
+        if(messageParams.length != 0) {
             String topic = messageParams[0];
             // owner and the deviceId are extracted from the MQTT topic to which the messgae was received.
             String ownerAndId = topic.replace(serverName + File.separator, "");
@@ -119,6 +120,7 @@ public class RaspberryPiMQTTConnector extends MQTTTransportHandler {
                         Calendar.getInstance().getTimeInMillis());
             }
         }
+    }
 
     @Override
     public void disconnect() {

components/device-mgt-iot-virtualfirealarm/org.wso2.carbon.device.mgt.iot.virtualfirealarm.controller.service.impl/src/main/java/org/wso2/carbon/device/mgt/iot/virtualfirealarm/controller/service/impl/transport/VirtualFireAlarmMQTTConnector.java

@@ -122,6 +122,7 @@ public class VirtualFireAlarmMQTTConnector extends MQTTTransportHandler {
      */
     @Override
     public void processIncomingMessage(MqttMessage mqttMessage, String... messageParams) {
+        if(messageParams.length != 0) {
             String topic = messageParams[0];
             // owner and the deviceId are extracted from the MQTT topic to which the messgae was received.
             String ownerAndId = topic.replace(serverName + File.separator, "");
@@ -172,6 +173,7 @@ public class VirtualFireAlarmMQTTConnector extends MQTTTransportHandler {
                 log.error(errorMsg, e);
             }
         }
+    }
 
     /**
      * {@inheritDoc}