As above.
Anyone know if it's possible?
-EDIT-
or MorphOS.
cheers,
There are two things to implementing Java. Firstly you need to implement the virtual machine itself. There is at least one example of this on OS3.x that I recall, a port of kaffe if I'm, not mistaken. I can remember playing with it ages ago - there's a reasonable chance it would work on OS4/MOS under emulation, though I imagine an emulated VM would potentially be very slow.
The second, and in some respects the more difficult task, is the runtime and associated class libraries, more pertinently the dependencies for the native interface.