Startup Issue with Minecraft - Latest Minecraft Java version (26.1.2) wont start

System Information

Field Value
Operating System Linux - Ubuntu 24.04.4 on x86_64
Product AMP ‘Deimos’ v2.7.2.6 (Mainline)
Virtualization None
Application Minecraft
Module MinecraftModule
Running in Container No
Current State Failed

Problem Description

Issue

I recently updated my Minecraft Java instance from 1.21.11 to 26.1.2. However, when i click start my Minecraft server wont start. AMP Tells me that AMP is not at fault and that i should check the console. This is the error in the console:

Uncaught exception in thread “main”

java.lang.RuntimeException: An exception occurred when launching the server!

Caused by: java.lang.RuntimeException: Error invoking MC server bundler: java.lang.UnsupportedClassVersionError: net/minecraft/bundler/Main has been compiled by a more recent version of the Java Runtime (class file version 69.0), this version of the Java Runtime only recognizes class file versions up to 65.0

Reproduction Steps

  • updated Minecraft Java edition from 1.21.11 to 26.1.2
  • ran the instance
  • opened the instence
  • clicked “start” to start the Minecraft sever
  • server wont start

Change the Java Version to 25.

i tried and the latest java version it would let me pick is java 21

Run getamp installJava as root then reboot.