Java & Launch Settings

mcl handles Java selection and launch arguments automatically before handing execution off to the game process.

Java management

Open Settings → Java to inspect discovered runtimes or manage installations:

• System discovery — Scans common installation paths and probes each java binary to verify major version, vendor, architecture, and compiler availability.
• Eclipse Temurin downloads — Install official Temurin JDK or JRE builds directly into mcl’s managed java directory with SHA-256 verification.
• Automatic resolution on launch — When launching an instance, mcl picks a compatible runtime matching the required Java major version and architecture, automatically downloading Temurin if no compatible local runtime is found.

Automatic memory allocation

Memory limits are calculated automatically during launch preparation:

• 64-bit Java: One quarter of system physical memory, clamped between 2048 MiB and 6144 MiB.
• 32-bit Java: 1024 MiB.
• Fallback: 2048 MiB if physical memory cannot be determined.

Game settings & GC strategies

Under Settings → Game, you can configure the garbage collection strategy (five built-in presets, with automatic ZGC generational flag compatibility for Java 23+) and validated custom JVM arguments. Changes save automatically in the background.

Launch workspace

Pressing Launch enters a dedicated preparation view that tracks asset verification, Java selection, session handoff, live process/window state, and sanitized session logs.