imagine following setup: I have multiple packages with entity beans. Currently each package contains a persistence.xml and the names of persistence units are different for each package. Each package is packed into a separate jar file. But all persistence units use the same data source and configuration.
In my opinion this doesn't make much sense. It would be easier to have only one persistence.xml containing the configuration only once and to use the same persistence unit in all packages.
What do you thing about it? For which case or for which reason would it be a good idea to have more than one persistence unit within an application?