ONOS-3839 Fixing errors in sending requests and hanging on future.join

Change-Id: I6da5bf1ff728efeb0d531cf7f04f6bf49f11a0a9
diff --git a/protocols/netconf/api/src/main/java/org/onosproject/netconf/NetconfDeviceOutputEvent.java b/protocols/netconf/api/src/main/java/org/onosproject/netconf/NetconfDeviceOutputEvent.java
index 0a140f1..f6ba4ab 100644
--- a/protocols/netconf/api/src/main/java/org/onosproject/netconf/NetconfDeviceOutputEvent.java
+++ b/protocols/netconf/api/src/main/java/org/onosproject/netconf/NetconfDeviceOutputEvent.java
@@ -91,14 +91,26 @@
         this.messageID = msgID;
     }
 
+    /**
+     * return the message payload of the reply form the device.
+     * @return reply
+     */
     public String getMessagePayload() {
         return messagePayload;
     }
 
+    /**
+     * Event-related device information.
+     * @return information about the device
+     */
     public NetconfDeviceInfo getDeviceInfo() {
         return deviceInfo;
     }
 
+    /**
+     * Reply messageId.
+     * @return messageId
+     */
     public Integer getMessageID() {
         return messageID;
     }