diff --git a/apps/openstacknode/app/src/main/java/org/onosproject/openstacknode/impl/DistributedOpenstackNodeStore.java b/apps/openstacknode/app/src/main/java/org/onosproject/openstacknode/impl/DistributedOpenstackNodeStore.java
index b636152..ea21db5 100644
--- a/apps/openstacknode/app/src/main/java/org/onosproject/openstacknode/impl/DistributedOpenstackNodeStore.java
+++ b/apps/openstacknode/app/src/main/java/org/onosproject/openstacknode/impl/DistributedOpenstackNodeStore.java
@@ -148,6 +148,9 @@
         return osNode == null ? null : osNode.value();
     }
 
+    /**
+     * An internal openstack node map listener.
+     */
     private class OpenstackNodeMapListener implements MapEventListener<String, OpenstackNode> {
 
         @Override