So while there's plenty of talk in here (even from the core lemmy devs) about how much it makes sense and how much value there is in starting a new project with a different tech stack that includes Java, compared to simply contributing back to the current project that has momentum ... and while that's an interesting and important conversation ...
Realistically, developers will make what they want to with what they want to (to a fault IMO, especially within the broader mission of the fediverse, but that's besides the point). This project will happen, people will contribute and it may succeed.
So, to focus on the positives and what can be made good about this ...
It's great that there's some sort of settling on a standard here and trying to be a "drop in replacement". Continued commitments to consistency and interoperability would be awesome. While collaboration may be naturally limited, there'd still definitely be scope for it ...
- ideas and designs, obviously
- Database management and optimisation, which is likely a big one.
- On that ... AFAICT, SL is using MySQL? Can't help but wonder (without knowing the technical justifications here) whether it would make much more sense to stick with the same DB unless there's a good reason for divergence.
- Front ends and the API, another big one but one where the two projects could conceivably work together.
I'm likely being very naive here, but I can see both projects coming under a single umbrella or compact which provide different backends and maybe DB setups or schemas but otherwise share a good amount in design and mission.
However unlikely that is ... trying not to fragment the fediverse too much would be awesome and its pleasant to see some dedication here to that end.