the builtin ipc mechanisms for each platform...it can be done, but is often a buggy/hard road unless very experienced. i would advocate instead the daemon get requests via a tcp/ip socket. there's already plenty of example daemon code out there (which is short and sweet) and you can concentrate on application logic instead of worrying about getting (semaphore/message queue/rpc/other tight coupled) ipc right. an example of this sort of setup is oracle OEM and tomcat manager application. anyhow, just a thought, as it also scales better and you can have the "client" connect from other machine(s).