Seems like an interesting effort. A developer is building an alternative Java-based backend to Lemmy’s Rust-based one, with the goal of building in a handful of different features. The dev is looking at using this compatibility to migrate their instance over to the new platform, while allowing the community to use their apps of choice.
I think you will find that the biggest reason to use a language is to get paid for it and there Java is very well positioned
That’s the reason for for hire devs yeah, but if you are starting a new project ( especially a community one like lemmy where the profit motive is different) choosing your tech stack is a complex decision