CurseForge · Minecraft mod

Scalar

The Scala 3 provider for Cleanroom

Choose a version Pick your version below, then grab the matching file.

Quick answer

Which Scalar release should I use?

Updated 13 days ago

Latest stable file scalar-3.9.0.jar

Game version 1.12.2

Loader Forge

scalar-3.9.0.jar targets 1.12.2 with Forge. The project page does not say whether this file belongs on the client, dedicated server, or both. No extra mods listed for this file.

Where it goes

Is Scalar required on the client, server, or both?

The project page does not say whether this file belongs on the client, dedicated server, or both.

Client Source doesn’t say

Dedicated server Source doesn’t say

Loader for this release Forge

Required install it here Optional supported, not mandatory Not supported do not install here Source doesn’t say do not assume

The source does not explicitly classify this release as client-only or server-only.

Understand client and server requirements Read the Minecraft installation guide

What else does scalar-3.9.0.jar need?

scalar-3.9.0.jar. Change the file and its required mods may change too.

No extra mods listed for this file

This file does not list any required mods. Do not add a library just because a different file uses it.

This file does not list any required or optional mods.

Before you install it

Add Scalar without breaking your instance.

Built for scalar-3.9.0.jar. Pick another file and the loader, install side or required mods may change.

01
Stick to this file

Use scalar-3.9.0.jar. It targets 1.12.2 with Forge; another release may have different loader, side or dependency requirements.
02
Bring the mods it needs

This file does not list any required mods. Do not add a library just because a different file uses it.
03
Put it on the correct side

The project page does not say whether this file belongs on the client, dedicated server, or both.
04
Pick the file you checked

Use the “Get this file” button beside scalar-3.9.0.jar. It opens that exact file at the source.

About this project

What does Scalar add?

Scalar is a Scala language provider for Cleanroom. It provides Scala 3 library for new Cleanroom mods.

Yes, you can develop with Scala 3 + Java 21 in 1.12.2!

If you want the Scalar providing Scala 2.11 which compats with legacy Forge mods, please use Scalar Legacy.

To run new Cleanroom mods developed in Scala 3 (like OpenComputers Rescaled), this mod is necessary.

FAQ:

Q: What is Cleanroom?
A: Cleanroom is a 1.12.2 Forge fork, providing newer toolchain, new APIs and 99% compatibility. Our plan is to make 1.12.2 up-to-date with latest toolchain while adding more feature to Forge & vanilla, so we don't need to care about higher versions' X point release * Y Mod API headache.
Q: How to install Cleanroom?
A: Please follow the instructions in README.
Q: Can I include this in my Forge modpack? Will it crash my Forge pack?
A: Yes, you can, and it is safe! This mod won't be loaded or crash anything in a Forge environment.
Q: Why make another project?
A: Putting Scala 3 provider and Scala 2 provider in same project keep producing confusion and unnecessary crash reports. So Scala 2 provider now belong to a new project.
Q: Why not just include Scala in the loader?
A: Scala 2.11 is deprecated and can't be compiled against under Java 21+. Our goal is not only providing a runtime but also latest development toolchain, so switching to Scala 3 is important. Make Scala become standalone mods is the only solution here.

Note: mod files marked as "Forge" because CurseForge doesn't support Cleanroom yet.

Project description from CurseForge.

Pick your setup

Scalar by Minecraft version and loader

Choose the version and loader you play, then open the matching release.

1 available setups

Minecraft version

1.12.2

1 loader build

Forge scalar-3.9.0.jar 6 stable files · 11 total · 3 Sept 2026

Check the dependencies, then try the file in a copied instance before changing a world you care about.

Recent files