java -jar JavaCPC.jar -Xms512m
If you run Arch Linux, you can also use the here is a [http://aur.archlinux.org/packages/javacpc/ JavaCPC AUR package].
Sound from the CPC can be a problem if the system is running PulseAudio (as most current Linux distos do). One possible workaround is simply killing the PulseAudio server before starting JavaCPC.