No, a "system on a chip" means the chip includes things that are not typically part of the CPU but were always parts of computer systems: busses, I/O, sometimes memory, auxillary HW functions like audio, image/video processing or codecs.
Nowadays CPU's often have a bunch of these things anyways and you'll hear that all CPU's sort of resemble SoCs. They also tend to have auxillary, lower-power processors that manage power and other things for the main processor.
3. Java Extension Module
The AVR32 architecture can optionally support execution of Java bytecodes by including a JavaExtension Module (JEM).
This support is included with minimal hardware overhead.
EDIT: Not by implementing the ISA verbatim, but still neat though
It doesn't make much sense to build hardware to run an intermediate language. Java bytecode isn't optimised; almost all optimisation is meant to happen in the JIT. If you build a processor that runs bytecode directly, when does the optimisation occur? Presumably never.
Low-horsepower platforms are probably the best place to give it a go, as they may struggle to run a respectable JIT compiler, but as you say, Jazelle didn't catch on.
The hardware would perform the optimisation using typical means. Instruction lookahead can be used for caching the stack slots to be used in registers, for instance.
