RFR: 8073148 "The server has decided to close this client connection" repeated continuously

[shanliang]

Hi,

Please review this fix:

Bug: https://bugs.openjdk.java.net/browse/JDK-8073148
Webrev: http://cr.openjdk.java.net/~sjiang/JDK-8073148/00/

A JMX server was called to close, it terminated at first its 
notification forwarder server, then closed its communication connection 
(RMI), but the closing thread was blocked at the connection termination, 
so a client fetch request would continue arriving and the server would 
reply immediately with 0 notification.

The fix is to ask server to return null to a client fetching request in 
case of termination, this informs a ClientNotifForwarder of the server 
termination, so the client can safely stop fetching.

The fix was tested in the environment where the bug was reported.

Thanks,
Shanliang