At SoftwareMill I participate in various projects, either as a technical lead, software engineer or project lead. We mainly use JVM-related technologies, either from the Scala stack (Akka, Spray, Scalatra) or Java stack (pure Java, JEE, Hibernate, Drools, JBoss technologies).
I'm the founder and main developer of ElasticMQ (a replicated, guaranteed messaging system), Hibernate Envers (an open-source entity auditing/versioning framework) and Veripacks (a transitive package usage verifier). I also work on static analysis related projects (using JSR-308 Typestate Annotations and FindBugs) and MenuBrowser (a utility program for MacOS written in Objective-C).
I was a speaker at major Java ...