* On Jython
Jython seemed like the obvious choice at first, except that it hasn’t had much momentum since around 2001. It used to be arguably the best non-Java JVM language around; Jim Hugunin did an amazing job with it. Unfortunately it’s had almost no love in the past six years, and it’s now lagging the Python spec by several major versions (2.2 vs. soon-to-be 2.6).
* On Rhino
* On open-sourcing the framework
We’ve talked about open-sourcing our “Rhino on Rails”, but so far it’s been no more than idle chit-chat. For one thing, work on the framework plays second fiddle to work on the actual application, so it’s progressing slowly, mostly as 20% work. For another, we’re dependent on various other Google infrastructure components that are themselves in the process of being open-sourced, although I don’t know if any of them have been announced yet.