From: Shing Wai Chan <shing.wai.chan_at_oracle.com>
Date: Mon, 27 Jun 2011 17:29:29 -0700

You can a async chat room sample code in
http://java.net/projects/glassfish-samples/sources/svn/show/trunk/ws/javaee6/web/servlet/async-request-war?rev=804

For a given browser, there is a max connections per target server.
This explains why there is a hang.

Regards,
      Shing Wai Chan