When a machine starts, it has to get its IP address some way or another. It could be a preset (hard-coded) adress, given by a DHCP server or set using some kind of peer-to-peer technology like rendezvous.

It is only when the machine has started and well established as a node in networked environment that it could start offering and/or looking for network services.

Here, Jini could start playing its role to help clients to connect to services and helping services to broadcast their existence and capabilities to potential clients.