checkstyle rule to check copyrights

Change-Id: Ia9bab40b5fe64fca539058a4316371f7acc0f387
diff --git a/core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/DefaultDistributedWorkQueue.java b/core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/DefaultDistributedWorkQueue.java
index d16c1b8..e11d42e 100644
--- a/core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/DefaultDistributedWorkQueue.java
+++ b/core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/DefaultDistributedWorkQueue.java
@@ -1,3 +1,18 @@
+/*
+ * Copyright 2016-present Open Networking Laboratory
+ *
+ * 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
+ *
+ *     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.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 package org.onosproject.store.primitives.impl;
 
 import java.util.ArrayList;