few changes to resolve start up issues

components/iot-plugins/androidsense-plugin/org.wso2.carbon.device.mgt.iot.androidsense.api/src/main/java/org/wso2/carbon/device/mgt/iot/androidsense/service/impl/AndroidSenseControllerServiceImpl.java

@@ -188,7 +188,7 @@ public class AndroidSenseControllerServiceImpl implements AndroidSenseController
                 if (waitForServerStartup()) {
                     return;
                 }
-                //The delay is added till the server starts up.
+                //The delay is added for the server to starts up.
                 try {
                     Thread.sleep(5000);
                 } catch (InterruptedException e) {

components/iot-plugins/digital-display-plugin/org.wso2.carbon.device.mgt.iot.digitaldisplay.api/src/main/java/org/wso2/carbon/device/mgt/iot/digitaldisplay/service/impl/DigitalDisplayControllerServiceImpl.java

@@ -253,6 +253,12 @@ public class DigitalDisplayControllerServiceImpl implements DigitalDisplayContro
                 if (waitForServerStartup()) {
                     return;
                 }
+                //The delay is added for the server to starts up.
+                try {
+                    Thread.sleep(5000);
+                } catch (InterruptedException e) {
+                    Thread.currentThread().interrupt();
+                }
                 DigitalDisplayControllerServiceImpl.digitalDisplayMQTTConnector = digitalDisplayMQTTConnector;
                 if (MqttConfig.getInstance().isEnabled()) {
                     digitalDisplayMQTTConnector.connect();

components/iot-plugins/raspberrypi-plugin/org.wso2.carbon.device.mgt.iot.raspberrypi.api/src/main/java/org/wso2/carbon/device/mgt/iot/raspberrypi/service/impl/RaspberryPiControllerServiceImpl.java

@@ -172,6 +172,12 @@ public class RaspberryPiControllerServiceImpl implements RaspberryPiControllerSe
                 if (waitForServerStartup()) {
                     return;
                 }
+                //The delay is added for the server to starts up.
+                try {
+                    Thread.sleep(5000);
+                } catch (InterruptedException e) {
+                    Thread.currentThread().interrupt();
+                }
                 RaspberryPiControllerServiceImpl.this.raspberryPiMQTTConnector = raspberryPiMQTTConnector;
                 if (MqttConfig.getInstance().isEnabled()) {
                     raspberryPiMQTTConnector.connect();

components/iot-plugins/virtual-fire-alarm-plugin/org.wso2.carbon.device.mgt.iot.virtualfirealarm.api/src/main/java/org/wso2/carbon/device/mgt/iot/virtualfirealarm/service/impl/VirtualFireAlarmControllerServiceImpl.java

@@ -391,6 +391,12 @@ public class VirtualFireAlarmControllerServiceImpl implements VirtualFireAlarmCo
                 if (waitForServerStartup()) {
                     return;
                 }
+                //The delay is added for the server to starts up.
+                try {
+                    Thread.sleep(5000);
+                } catch (InterruptedException e) {
+                    Thread.currentThread().interrupt();
+                }
                 VirtualFireAlarmControllerServiceImpl.this.virtualFireAlarmMQTTConnector = virtualFireAlarmMQTTConnector;
                 if (MqttConfig.getInstance().isEnabled()) {
                     virtualFireAlarmMQTTConnector.connect();