I'm having a problem. I got a script in a unix that works just fine when I run it from the shell. But when I run the script from Java (and it runs, I got the script's log to see it) it gets a "no permission granted"

With that, I wonder what unix user is used when Java launchs a unix script?
Besides that, there's any way to Java to force unix to run the script with a specific user, kind of run as?