j2cl

Well, for Java it's actually a separate compiler that targets Wasm and integrates with WasmGC: https://github.com/google/j2cl The Google Sheets team used it for their calc engine: https://v8.dev/blog/wasm-gc-porting For Kotlin it's similar but the compiler backend is from Jetbrains themselves, targets Wasm and adapts the Kotlin runtime to use WasmGC: https://kotlinlang.org/docs/wasm-overview.html. https://seb.deleuze.fr/introducing-kotlin-wasm/ has some low level detail on how Kotlin works with WasmGC. A bit more on Kotlin/Wasm here, seems like also Dart/Flutter uses WasmGC: https://developer.chrome.com/blog/wasmgc#kotlin_wasm https://github.com/dotnet/runtime/issues/94420 has some notes on why C# can't use WasmGC (yet?).

also https://github.com/mirkosertic/Bytecoder and https://github.com/i-net-software/JWebAssembly as well as the already mentioned (in some other comment) https://cheerpj.com/ most of them are still experimental, while CheerpJ offers Enterprise support (but it targets the browser). oh, and let's not forget j2cl https://github.com/google/j2cl