Apache Jakarta Commons Mapper
Most Java applications must store data to a data store whether it’s XML files or a relational database. Changes to the mapping technology should be transparent to the rest of the application allowing changes to be localized in the mapping layer. Commons Mapper is a thin abstraction layer around a project’s chosen data mapping technology. It allows the developer to vary the mapping technique behind this layer (often combining several technologies) so that the rest of the application doesn’t change.