Hi, For anyone who's interested in this kind of stuff, I just uploaded my pure-ruby toy JVM to Rubyforge. It's obviously very slow, but can be useful for seeing how things work or debugging generated classes that won't verify. It can do some reasonable class-dumps and execution traces, too. It's probably about 70% complete, with most instructions implemented, and currently has some integration with the GNU Classpath runtime library. http://ruva.rubyforge.org/ http://rubyforge.org/projects/ruva svn checkout svn://rubyforge.org/var/svn/ruva/trunk -- Ross Bamford - rosco / roscopeco.REMOVE.co.uk