I have a project where the application will run on both Windows and Solaris, however, the program is required to make some system calls only on the Unix side. I was thinking of setting up an RMI server on a Unix machine and have my client application execute the system calls on the remote machine. My alternative would be to use RSH, which gets messy when you want your app to work on both Unix and the PC. My question is about user permissions. The system calls must be executed as the user who launched the client application. Is it possible to switch users? Do I have to always launch the RMI server as root? Thanks for any info or alternative ideas.