description added for exception: JavaDoc warning fixed

Change-Id: Ifd58774b11e3776c4c8c3211e0a9035bd5be7c6d
diff --git a/apps/vtn/vtnweb/src/main/java/org/onosproject/vtnweb/resources/FloatingIpWebResource.java b/apps/vtn/vtnweb/src/main/java/org/onosproject/vtnweb/resources/FloatingIpWebResource.java
index 9fdcb52..f7e97d5 100644
--- a/apps/vtn/vtnweb/src/main/java/org/onosproject/vtnweb/resources/FloatingIpWebResource.java
+++ b/apps/vtn/vtnweb/src/main/java/org/onosproject/vtnweb/resources/FloatingIpWebResource.java
@@ -187,7 +187,7 @@
      *
      * @param floatingIpNodes the floatingIp json node
      * @return floatingIps a collection of floatingIp
-     * @throws Exception
+     * @throws Exception when any argument is illegal
      */
     public Collection<FloatingIp> changeJsonToSub(JsonNode floatingIpNodes)
             throws Exception {