At SavaJe’s faq you can read:
The kernel, device drivers, JVM, graphics, media framework and other low-level code is written in C or C++. The rest of the platform code is written in Java.
SavaJe OS is a complete operating system and applications platform. It includes a kernel and an integrated JVM, but it differs from other mobile Java solutions in that the JVM is an integral part of the platform, which allows efficient execution of Java code. Because Java is the application language for SavaJe OS, the JVM is less virtual than on other mobile platforms. In addition to the kernel and the JVM, SavaJe OS includes a complete set of applications and a reference UE (user experience) implementation.
SavaJe is not only a JVM!
SavaJe is an OS based on Java!
I found that SavaJe is in the conference Pavilion at this year JavaOne 2006, perhaps they have any device to show, I hope so!, a very interesting solution!