diff --git a/apps/vtn/vtnweb/src/main/java/org/onosproject/vtnweb/resources/RouterWebResource.java b/apps/vtn/vtnweb/src/main/java/org/onosproject/vtnweb/resources/RouterWebResource.java
index 8c2a2b3..6f80dd1 100644
--- a/apps/vtn/vtnweb/src/main/java/org/onosproject/vtnweb/resources/RouterWebResource.java
+++ b/apps/vtn/vtnweb/src/main/java/org/onosproject/vtnweb/resources/RouterWebResource.java
@@ -293,7 +293,7 @@
      *
      * @param routerNode the router json node
      * @return routers a collection of router
-     * @throws Exception
+     * @throws Exception when any argument is illegal
      */
     public Collection<Router> changeJsonToSub(JsonNode routerNode)
             throws Exception {