ModsJava
BetterRandomSourceConcurrencyCrash
Java mod listed for Minecraft 1.19–1.21. Downloads from the MC Java Mods app on Android.
I don't know my version or loader
Open the Minecraft launcher and look at the profile you play on — it names both, like fabric-loader-1.21.4. The version also shows in the bottom-right corner of the game's main menu.
No loader in the profile name? Then it's plain Minecraft, and these mods won't run — you need Fabric or NeoForge installed first.
This mod improves the logging when a mod accesses a LegacyRandomSource from the wrong thread, causing a java.lang.IllegalStateException: Accessing LegacyRandomSource from multiple threads crash, by adding information about the second thread involved in the crash.
Disclaimer: This mod is purely intended for debugging and should not be installed unless needed for debugging due to the overhead it adds to the LegacyRandomSource!
Quick facts
- Edition: Minecraft Java
- File type: .jar
- Minecraft versions listed: 1.21, 1.21.1, 1.20.4
- How to install: Install the matching mod loader (Forge, Fabric or NeoForge) for your Minecraft version. → Download the .jar. → Put it in the .minecraft/mods folder and launch that loader profile.
- Where to get it: Opens on CurseForge — not every file is mirrored on our own servers.
Install steps are the general flow for this file type — How to install Minecraft Java mods & modpacks walks through it step by step.
File checked by MCModsHub
- Ships as BetterRandomSourceConcurrencyCrash-2.0.jar — drop this file into the mods folder
- Download size: 33 KB
- Download link checked 26 Sept 2026 — working
These come from our own check of the pack file, not from the source page.