I've just started working with the compiler API for an AB5k desklet. It's a lot more than I need, but looking at the API, it's clear that they've anticipated some pretty elaborate uses and provide a significant amount of flexibility for those who are able and willing to take advantage of it. I'm not terribly satisfied with the documentation, though -- creating a compilation task takes an "options" parameter that I have yet to find documentation of.

Could this API be used to create a dynamic extension to a running Java application, so that a module receives a block of code and generates a new class, which is then available to the running application? I'm thinking of an eval idea -- the ability to extend dynamically running Java applications. For example, by wrapping the above functionality, you could support something like Ruby's ability to dynamically extend a class -- a module could receive a class file and method code to be added (for example), combine them, and pass them to the API to parse and generate a new class. Then the newly created extended class is available in the same process.