Kaffe is a lean, fast and portable virtual machine. It is a small VM, when compared to the original JVM, so it appeals to embedded system developers. It comes with just-in-time compilers for many of the CPU architectures it has been ported to, more than 70 system platforms in total. It runs on devices ranging from embedded SuperH devices to zSeries mainframes. It even runs on PlayStation2.
Kaffe is free software. It is licensed under the terms of the GNU General Public License (GPL). It is being developed by a world-wide team of hackers. Beside the mailing list, the developers can often be reached via IRC on #kaffe on irc.freenode.org.