Quite interesting project... It looks like lightweight implementation of Intershop Enfinity Studio (www.intershop.com/). I like such architectural features as flow, flowlet, template. Very easy to extend functionality, find bug and understand code. Easy to support existing code. Unfortunately, Flow4J-Eclipse is not actively developed / supported anymore. There is other similar open-source implementation on GitHub. (github.com/neuro4j/studio). It is also free and in active development.