Can NetworkInterfaceBinding return a Set<NetworkInterface> ?
Also, should SocketBinding.createMulticastSocket() be joining the group? Once it has created ManagedMulticastSocketBinding it has performed it's core mission of making sure the socket can be tracked. The caller can be responsible for other tasks, with SocketBinding just being responsible for provided all needed configuration information.
Somewhat related, I opened https://jira.jboss.org/browse/JBAS-8470 . We can deal with that after M1, if needed, as I don't think createMulticastSocket() is actually going to be used in M1.