ForceJava21
A somehow stupid and cursed mod that forces you to launch 1.16.5 with Java 21 and Forge 36.2.41 +.
About this Mod
ForceJava21
A somehow stupid and cursed mod that forces you to launch Minecraft with Java 21 (and, if you are on 1.16.5, Forge 36.2.41 + is required).
If you are trying to launch Minecraft with Java 20 or below, the following texts will appear in your log, and the game will stop immediately.
Please use Java 21 (and Forge 36.2.41+) to launch Minecraft.
Current Java version: yourJavaVersion. Current Forge version: yourForgeVersion
Recommendations:
Zulu: https://www.azul.com/downloads/?version=java-21-lts&package=jdk#zulu
Oracle: https://www.oracle.com/java/technologies/downloads/#java21
Temurin: https://adoptium.net/temurin/releases/?version=21
But... how can you launch 1.16.5 forge with Java 21?
You can. For details, see #9825.
Misc
Available Versions
How to Install ForceJava21 on Your Server
Order Server
Order a Minecraft Java server with at least 3 GB RAM (4 GB recommended).
Set forge Loader
In the panel under "Egg", select the forge loader and matching Minecraft version (1.20.1).
Install Mod
Open the mod browser in the dashboard and search for "ForceJava21". Click "Install" – done! Alternatively, upload the .jar via SFTP to the /mods folder.
Compatibility
Mod Loaders
Minecraft Versions
1.20.1, 1.20, 1.19.4 (+5 more)
Server-side
✓ RequiredRecommended RAM
4 GB(min. 3 GB)Frequently Asked Questions
ForceJava21 server crashes on startup – what to do?
Most common cause: wrong forge version or insufficient RAM. Check the server log (latest.log) for "OutOfMemoryError" or "Mixin" errors. With Mado Hosting: ensure at least 3 GB RAM is allocated and the loader matches the mod version (1.20.1). You can switch loaders with one click in the panel.
Is ForceJava21 compatible with forge?
ForceJava21 officially supports forge for Minecraft 1.20.1, 1.20, 1.19.4. The Mado dashboard automatically detects incompatible loader combinations.
Server lagging with ForceJava21 – how to optimize performance?
Recommended RAM: 4 GB (per 8 players). Use /spark profiler to check if ForceJava21 consumes the most tick time. Common fixes: reduce server view-distance to 8-10, install "performant" or "starlight" as supplementary mods on Forge. With Mado Hosting, your server runs on NVMe SSDs with dedicated CPU cores for minimal latency.
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Rent Modded Server
Install ForceJava21 with just one click on your server.