I can partially answer my own question. Nothing to do with glassfish.
I can use
hostName = InetAddress.getLocalHost().getHostName();
to get the host name (although in my local network environment, my Mac OS X is identified with a bogus host name) and
ipAddress = InetAddress.getLocalHost().getHostAddress();
to get the IP address -- this seems to be accurate even for my Mac.
Adding InetAddress and associated exceptions to my import list of course.
This does not give me the port that the wrapping app server is running on.
But at least this is a start to tell running instances apart.
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