This is not the latest branch of the game, see this repo for the C# branch.
You can read about why the game was rewritten in C# later on here
This is the Java branch of Burning Knight, the second version of the game (first one was written in Lua, but it only lasted for 3 days). I have to warn you, the code is not pretty. In fact, looking back at it, it's awful. But non the less, I've learned so much from this mess, and I tried my best to make the C# branch a lot better (and I think it worked out really well).
So. Have fun exploring this jungle. It might be a bit hard to compile, it requires some older gradle version, and I haven't figured out how to update the gradle build files to the latest syntax.
I hope, that this might be useful to someone. And if so, I'm glad. If you want to get the latest game, it's available on Steam.