bah, si c'est sous unix, tu peux faire avec xinetd :
NAME
xinetd - the extended Internet services daemon
SYNOPSIS
xinetd [options]
DESCRIPTION
xinetd performs the same function as inetd: it starts programs that provide Internet services. Instead of having such servers started at system initialization time, and be dormant
until a connection request arrives, xinetd is the only daemon process started and it listens on all service ports for the services listed in its configuration file. When a request
comes in, xinetd starts the appropriate server. Because of the way it operates, xinetd (as well as inetd) is also referred to as a super-server.
Comme ça, tu définis ton service, et ton serveur sera démarré dès qu'une connection se fera sur le port de ton serveur RMI...Bon, je l'ai jamais fait, mais ça doit pas etre insurmontable...