Check for NPE

application/src/main/java/org/thingsboard/server/service/telemetry/DefaultTelemetrySubscriptionService.java

@@ -1,12 +1,12 @@
 /**
  * Copyright © 2016-2018 The Thingsboard Authors
- * <p>
+ *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * <p>
- * http://www.apache.org/licenses/LICENSE-2.0
- * <p>
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.