These days, I'm mostly working on making the Java platform even more hospitable for a wide variety of programming languages that can target it.
I used to be actively involved in several open source projects. Most notably, I was the project administrator of the FreeMarker project (open source template engine in Java) as well as a contributor (and former maintainer) of the Mozilla Rhino project (the original JavaScript runtime on the JVM). I've also created the Rhino-in-Spring web flow framework, and am currently leading the effort to define a standard linker framework and metaobject protocol for all dynamic languages on the JVM as part of my Dynalink project.
During my time at Twitter, ...