User story: I'm developing a new program and try to put as much program logic into different libraries as possible to increase the reusability.
For interfaces where only a single library or "module" is needed, it is easy. Simply add the library to the project and work with the interface of the library.
Problem: But now I want to outsource the processing layer, which I have to split in different libraries. Therefore I need to build an integration which supports such a structure.
I have looked into Java 9 but it seems it will not fit this use case.
How would a best practice for this use case look like?