I'm stepping out of my territory to talk about this framework I know nothing about: OpenXava. OpenXava is a framework for creating Enterprise Applications with Java based solely on the annotated model (the Controllers are reused and the View are generated automatically).
Microsoft is heading to the same point through a different path - DSL Tooling. ASP.NET Dynamic Data Support does something from the model defined.
But this framework seems to be ahead in terms of maturity and implementation. This is the way I imagine implementing some of our enterprise applications on the near future, designing and annotating the model (through designers, hopefully not code), overriding extending and customizing a bit, arming some events when needed and creating validators, business rules and processors.