I don't know of a way to find out which Server the app was loaded from, if one is using JWS. But since you need more info anyway (like, the port number) why not specify the info needed in the jnlp file?
<property name="jboss.server" value="serverNameOrIP"/> <property name="jboss.port" value="portNum"/>
That way, you can access the info using
System.getProperty("jboss.server") and System.getProperty("jboss.port")
to retrieve the values.
This also has the added benefit that you can still start your app without JWS, simply by adding
-Djboss.server=serverName -Djboss.port=portnumto the command line (nice for debugging the client).
Not exactly what you're asking for, but maybe that helps.
this is maybe a solution. I think this will help.