Throwing exception on getDevice when device is not found

components/device-mgt/org.wso2.carbon.device.mgt.core/src/main/java/org/wso2/carbon/device/mgt/core/service/DeviceManagementProviderServiceImpl.java

@@ -823,11 +823,12 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
             DeviceManagementDAOFactory.openConnection();
             device = deviceDAO.getDevice(deviceId, this.getTenantId());
             if (device == null) {
+                String msg = "No device is found upon the type '" + deviceId.getType() + "' and id '" +
+                        deviceId.getId() + "'";
                 if (log.isDebugEnabled()) {
-                    log.debug("No device is found upon the type '" + deviceId.getType() + "' and id '" +
-                            deviceId.getId() + "'");
+                    log.debug(msg);
                 }
-                return null;
+                throw new DeviceManagementException(msg);
             }
             DeviceInfo info = deviceInfoDAO.getDeviceInformation(device.getId());
             DeviceLocation location = deviceInfoDAO.getDeviceLocation(device.getId());