PID file for java process?

I need to start a java process and get a valid pid for it to be able to kill it later. So, I thought I could use startproc in this way 'startproc -f -p /var/run/myproc.pid /usr/bin/java/ jarfil.jar' But noway.. I don't get a pid file at all. So, how should I do to get a valid pidfile for the process? Anders.