The "Wasm GC" tag refers to a cutting-edge web standard that integrates garbage collection directly into the WebAssembly engine itself, rather than routing it through JavaScript.
Eaglercraft 1.12 demonstrates that for complex Java-to-WebAssembly games. It delivers:
Item stacks, NBT data, and crafting recipes are now managed as WASM GC arrays of references. Swapping items in a chest? That’s just moving a reference inside WASM—no JS involved. eaglercraft 112 wasm gc
is a binary instruction format that serves as a compilation target for languages like C, C++, Rust, and... Java (via tools like TeaVM). It is designed to be a portable, low-level abstraction that runs at near-native speed in modern web browsers. Unlike JavaScript, which is interpreted and can be unpredictable in terms of performance, WebAssembly code is compiled ahead of time and executed in a tightly-controlled sandbox.
: Smoother chunk generation thanks to efficient threading and memory handling. Lower Hardware Requirements The "Wasm GC" tag refers to a cutting-edge
Here is the problem: JavaScript also has a garbage collector, but it is not optimized for the way Minecraft creates memory churn. Every time a block breaks or a player moves, thousands of small objects are created. In JavaScript, this causes the browser’s GC to fire aggressively, leading to:
Ready to try it for yourself? The best place to start is by downloading a pre-built client from a trusted source. Websites like mc.js.cool often provide the latest builds, with some offering a user-friendly launcher that lets you instantly choose between the standard JavaScript version and the wasm_gc version for 1.12. Swapping items in a chest
| Metric | Eaglercraft (old JS heap) | Eaglercraft 1.12 (WASM GC) | |--------|---------------------------|-----------------------------| | GC pauses (avg) | 45–80 ms (every ~2 sec) | <5 ms (rare, ~every 15 sec) | | Chunk load stutter | Yes (15–30 ms freeze) | None (async & smooth) | | Memory after 1 hour | 1.2–1.8 GB | 450–600 MB | | Tab crash likelihood | Medium–High | Very Low |
For developers and enthusiasts, building your own wasm_gc client is a straightforward process. The pre-made workspace for EaglercraftX (which includes the 1.8 version) provides a clear blueprint, and a similar process applies for version 1.12. In that workspace, you simply run the MakeWASMClientBundle script within the "target_teavm_wasm_gc" folder, or execute the corresponding makeMainWasmClientBundle Gradle task from your integrated development environment (IDE). This process builds the WASM-GC client, producing an assets.epw file that bundles all the code and assets.
Want to dive deeper? Check out the official Eaglercraft GitHub (WASM GC branch) and TeaVM’s GC backend documentation.