But it wasn't magic. Wasm GC lacked finalizers, so native resources (like WebGL textures) still needed manual cleanup. The class hierarchy of Minecraft — TileEntity subclasses, IRecipe types — all required precise casting support. And the biggest hurdle: reflection. Minecraft 1.12’s ObfuscationReflectionHelper and dynamic proxies broke. Alex had to write a custom transformation pass at compile time to replace reflective calls with direct Wasm GC casts.
The first test was a superflat world with 64 villagers. On the JS backend, frame rate dropped to 15 FPS with major GC spikes every 5 seconds. On Wasm GC? A steady 45 FPS. No visible hitches. The collector ran concurrently, reclaiming entire chunks of blocks and entity pathfinding data without stopping the world — in both senses. eaglercraft 1.12 wasm gc
Then came the experiment: .
And the browser’s garbage collector just hummed along, quietly collecting fallen leaves in the background. But it wasn't magic
Alex recompiled the 1.12 client using a custom TeaVM fork targeting Wasm GC. Instead of outputting JavaScript heap management, every object allocation, every new BlockPos() , every HashMap of entities — all became Wasm GC structs and arrays, traced and collected by the browser’s optimized garbage collector. And the biggest hurdle: reflection