Startup Issue with Minecraft - minecraft server not starting up

System Information

Field Value
Operating System Linux - Debian GNU/Linux 12 on x86_64
Product AMP ‘Callisto’ v2.5.0.8 (Mainline)
Virtualization Docker
Application Minecraft
Module MinecraftModule
Running in Container Yes
Current State Failed

Problem Description

Issue

Minecraft server not starting up. Console says something about the java version not being compatible. Dont know how to change java version or anything. error is this version of the Java Runtime only recognizes class file versions up to 61.0. the server is running on version 65.0.

Reproduction Steps

  • downloaded mods
  • downloaded a saved world from a different server provider
  • tried booting world and it doesnt boot

You need Java 21 to run MC 1.20.6