Today it hit Debian unstable, so upgrade my sid32 chroot and had Cacao run Jmol. I had some memory issues opening a small molecule [1], and the rendering speed was a factor 100 or so slower than Sun's JVM, but it runs!
Using the command cacao -Xmx512M -jar Jmol.jar triplebond.mol I got:

Note the exceptions copied to the console. I'll paste the full stack trace as a comment.
Many thanx to the Classpath team!
1.InChI=1/C6H10/c1-4-5-6(2)3/h6H,1-3H3