The problem with these things is not the VM, but the classes. JavaVM uses GNU classpath, and assuming you want to have graphics that pulls in quite a list of dependecies. The history of "java for amiga" is very long. The problem is always the same: the classes.
tl;dr: Port the dependecies first.
Anyway, we've had some sort of java for a decade or so. Why no-one notices or cares is another topic. See
http://www.jamiga.org/ (Whether JAmiga is up to date with today's java standards is another topic as well. Does anyone know how well it fares?)
