diff --git a/apps/vtn/vtnmgr/src/main/java/org/onosproject/vtn/util/DataPathIdGenerator.java b/apps/vtn/vtnmgr/src/main/java/org/onosproject/vtn/util/DataPathIdGenerator.java
index c241347..93be3d1 100644
--- a/apps/vtn/vtnmgr/src/main/java/org/onosproject/vtn/util/DataPathIdGenerator.java
+++ b/apps/vtn/vtnmgr/src/main/java/org/onosproject/vtn/util/DataPathIdGenerator.java
@@ -1,3 +1,18 @@
+/*
+ * Copyright 2015-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.vtn.util;
 
 import static org.onlab.util.Tools.toHex;