in several projects we have implemented yet we found out that there are some aspects that we use again and again. For example we have defined a SLSB that provides other modules with auto generated IDs in a predefined format. The SLSB works with one conifguration entity in the background. What I would really like is to define a separate jar or ear that can be linked to all projects that need specific ID generation. I think that one problem is to work with multiple persistence units. What are further traps? Or is it maybe better to keep the hands off such an implementation?