Garbage Collection (GC) is the automatic memory management system in languages like Java and JavaScript. While convenient, it comes with a problem: stop-the-world pauses.
In a traditional Eaglercraft setup:
For an action game requiring 60 frames per second, these stutters are lethal. This is why early Eaglercraft versions capped out at 1.8. The Java Stop-The-World GC translated poorly into JavaScript.
Enter WASM GC.
For years, the promise of "Minecraft in a browser tab" came with asterisks. Lag spikes. Memory leaks. Tab crashes. Then came Eaglercraft 1.12, and with it, a quiet revolution under the hood: WASM Garbage Collection (WASM GC).
If you haven't been following the underground browser gaming scene, here’s why this update is a seismic shift—not just for block-breaking enthusiasts, but for web-based Java applications as a whole.
Several public Eaglercraft 1.12 servers now ship with the WASM GC build: eaglercraft 112 wasm gc
Note: Some anti-cheat plugins flag WASM GC builds as modified clients. Use on servers that support Eaglercraft natively.
Eaglercraft 1.12 is an open-source, browser-based port of Minecraft Java Edition 1.12.2. Unlike traditional ports that rely on JavaScript or legacy asm.js, Eaglercraft runs directly in the browser using WebAssembly (WASM). The latest evolution in its runtime incorporates WASM Garbage Collection (WASM GC) — a new proposal that allows WebAssembly modules to manage language-level heap objects more efficiently, bridging the gap between low-level WASM and high-level managed languages like Java.
This write-up explores how Eaglercraft 1.12 implements WASM GC, its performance benefits, and the trade-offs compared to earlier JavaScript-based or manual-memory-managed WASM approaches. Garbage Collection (GC) is the automatic memory management
Eaglercraft is a project that ports Minecraft Java Edition to run natively in a web browser using WebAssembly (WASM) and JavaScript. It doesn’t require a Java plugin, a Minecraft account, or any server-side Java runtime — everything runs client-side in HTML5/JS.
The original Eaglercraft focused on older Minecraft versions (e.g., 1.5.2, 1.8.8). However, the community has pushed toward Minecraft 1.12.2, a highly modded and feature-rich version.
Older versions of Eaglercraft (e.g., 1.8) used: For an action game requiring 60 frames per
The core problem: Java’s implicit memory allocation becomes unpredictable when translated to JS, leading to GC churn and frame drops.