ModsFinder

Cleanroom Relauncher

by Cleanroom

Cleanroom Relauncher starts a Forge 1.12.2 instance with the Cleanroom loader, so the game can run with a newer Java runtime.

ForgeClient-side onlyMIT LicenseOpen source1.12.2

What it does

When the instance launches, the relauncher restarts Forge 1.12.2 with Cleanroom in place of the stock loader. It installs the latest Cleanroom-compatible Java runtime automatically, and Java builds it has already fetched are cached under .cleanroom relauncher java so later launches reuse them. Nothing has to be installed by hand beyond the mod itself.

An Advanced Settings panel lets the player pick the Java version, the install location and the JVM flags used for the relaunch. Those values can also be changed later in the in-game config menu, so the setup is not fixed at install time. The mod is released under the MIT License and is open source, and its source code and issue tracker are public.

Cleanroom expects the Fugue fix to be present for some older Forge mods, and Scala mods depend on Scala 2 components. The mod is published for Forge 1.12.2 only, with the latest file, 1.2.1, dated 2026-10-15, and has been on the catalog since 2025-03-06. Bobby Legacy, DimensionalLayers and Efficient Entities all require it.

Key features

  1. Cleanroom relaunch

    Restarts the Forge 1.12.2 instance with Cleanroom, using the loader's own launch path.

  2. Automatic Java provisioning

    Installs the newest Cleanroom-compatible Java runtime and keeps the copies it has installed in a local cache.

  3. Advanced launch settings

    Exposes Java version, install path and JVM flags, which stay editable in the in-game config menu.

Compatibility

Latest build for each game version and loader.

1.12.21.2.1
ReleaseBetaAlphaNot available

Only full game releases are shown. This mod publishes no snapshot builds.

Required by 3 mods

Bobby Legacy1.12.2DimensionalLayers1.12.2Efficient Entities1.12.2

Use cases

Running Scala-based mods

Mods that depend on Scala 2 components can start under the Cleanroom setup this mod provides.

Loading older Forge mods with Fugue

Cleanroom expects the Fugue fix for some older Forge mods, and the relaunch keeps that requirement in place.

Who it’s for: Players and modpack builders on Forge 1.12.2 who want Cleanroom's launch path and a Java runtime chosen for them. Server owners do not need it, because the environment is client-side only.

Questions

Does Cleanroom Relauncher need to be installed on a server?

No. It is installed on the player's side alone, so servers need nothing.

Which Java version does the relaunch use?

The mod installs the latest Cleanroom-compatible Java runtime by default. Advanced Settings can select another installed version, and the choice can be changed later in the in-game config menu.

Why do Bobby Legacy and Efficient Entities need this mod?

Both list Cleanroom Relauncher as a required dependency, so it must be installed with them on Forge 1.12.2.

In the catalog

Cleanroom Relauncher is one of 3,545 Optimization mods on ModsFinder, and one of 1,441 Optimization mods for Forge. 2,920 mods support Minecraft 1.12.2.

Optimization mods3,545Forge modsMods for 1.12.22,920

More from Cleanroom

All projects
ConfigAnytime1.12.2Had Enough Items1.12.2AssetMover1.12.2Flare (Spark for 1.12.2)1.12.2

Similar mods

Entity Cullingb1.7.3 – 26.3Distant Horizons1.12.2 – 26.3Packet Fixer1.12.2 – 26.3Let Me Despawn1.12.2 – 26.3AI Improvements: Performance Tuning1.7.10 – 26.3Alternate Currenta1.0.11 – 26.3

What the author says

Relaunches a Forge 1.12.2 instance with Cleanroom.
Cleanroom, on the Modrinth page

Official listing

Owner
Cleanroom
Published
2025-03-06
Updated on Modrinth
2026-10-15
Facts verified
2026-10-15

Tags

LibraryManagementOptimization
Open on ModrinthCompare