Java App Tunnels and Mac

Does anyone know whether this works or not? I've reviewed threads that indicate the tunnels appear on loopback ports which are assigned dynamically, which would make them next to useless with multiple tunnels from a end-user perspective. I've also been told by F5 that app tunnels won't work with new versions of OSX/Safari due to a change in the OSX Java programming interface but firefox should work ok. I've yet to get any Mac app tunnels working. Obviously network access is an alternative but I'm keen to understand whether this documented feature actually works and others experiences with it?