I've been doing a lot of research on Hexagonal Architecture aka ports and adapters. I like the concepts, but struggling with some of the practicality. For example, the Domain isn't supposed to have the database access details (implementation). Instead that should be in the Framework layer. But there's a lot of "smarts" involved with data access in order to get the right data and it would seem to me that should belong in the Domain? So I'm looking for an example Java project that practically demonstrates the interactions between the Domain, Application, and Framework layers. Anyone know if something like this exists? I've not had much luck finding it. Lots of blogs about Hexagonal Architecture concepts, but nothing with concrete examples.