Configuration with Minecraft - Issue adding Aikar's flags on Minecraft Fabric server

System Information

Field Value
Operating System Linux - Ubuntu 24.04.4 on x86_64
Product AMP ‘Proteus’ v2.8.0.0 (Mainline)
Virtualization None
Application Minecraft
Module MinecraftModule
Running in Container No
Current State Ready

Problem Description

Issue

Hello, this is like a fifth time I am setting up modded Minecraft server, and for the first time I am getting a strange occurance of instance going into idle state whenever I insert any additional java arguments. Can you please assist me with that?

Pasting just -XX:+UseG1GC for example will already cause the issue on my end.

Reproduction Steps

    1. Add Aikar’s flags in Java Additional Arguments of Minecraft server config.
    1. Restart the server.
    1. Server goes into Idle state.

Edit - update:

Final confirmation that this is isolated to AMP’s launch handling. I stopped the AMP instance and launched the exact same jar from the exact same instance directory using AMP’s exact configured Java binary, with the full flag set, manually via SSH:

/usr/lib/jvm/temurin-21-jdk-amd64/bin/java -Xms14G -Xmx14G -XX:+UseG1GC -XX:+ParallelRefProcEnabled ... -jar fabric-server-launch.jar nogui

-> The server boots and runs perfectly with all flags applied.
But putting the same flags in the panel’s “Additional Java Options” makes the instance go idle. Same Java, same jar, same flags, same directory, works from CLI, fails through AMP.