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 the people who say this and think Rust is the second coming of Jesus, just don’t code. You choose the right language that’s needed for the job. Server stuff like this is Java’s bread and butter. As amazing as Rust is, it has proven to not be a great choice for Lemmy’s development.