Where I was able to mention earlier that JChemPaint now runs with free (as in open source) Java virtual machines, I just tried to run the core Jmol renderer, using the Integration.java which comes as an example:
The screenshot was made with jamvm 1.3.3 and classpath 0.19.
It is very slow, however. I have not tried it with other free virtual machines, which are supposedly faster. It is a good start nevertheless: it means that a Jmol based Bioclipse plugin will work with free virtual machines too.
Update: added a nicer screenshot.