Good news on the generator front - VOC fully supports generators, lambdas, passing functions as arguments, and all sorts of things that Python allows but Java (the language) doesn't.

As for a guide to calling Java from Python - we don't have any good documentation for this (yet), but it's entirely possible. Here's a sample Android application. If you're familiar with the Android APIs, you should be able to see the syntax conventions in place. https://gist.github.com/freakboy3742/7beb22c587e57240610777a...