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Minecraft Java instance cannot switch to required JDK version for latest 1.18 pre-release snapshots

  • Last Post 21 November 2021
Stort posted this 20 November 2021

OS Name/Version: Debian 10

Product Name/Version: AMP Release "Triton" v2.3.0.4

Problem Description:

I'm running a Minecraft instance in an AMP install on a Debian VPS, the instance has been keeping up with the 1.18 snapshots so far, but today I upgraded from "1.18-pre1 (snapshot)" to "1.18-pre5 (snapshot)" and now when I attempt to start Minecraft it fails and gives the following error in the console -

Error: LinkageError occurred while loading main class net.minecraft.bundler.Main java.lang.UnsupportedClassVersionError: net/minecraft/bundler/Main has been compiled by a more recent version of the Java Runtime (class file version 61.0), this version of the Java Runtime only recognizes class file versions up to 60.0

Seems that the newest 1.18 snapshots require JDK 17 to run, and this version is not available in the AMP configuration options.

Steps to reproduce: 1. Setup a Minecraft Java Edition instance in AMP v2.3.0.4 2. Start a new world on the latest Minecraft snapshot version (1.18-pre5 snapshot, though it has apparently been an issue since 1.18-pre2) 3. Attempt to start the game server in the instance and look at the console

Actions taken to resolve so far: First attempted to change the JDK version in the configuration settings, but it was already on the latest version available in the list (v.16). I then updated AMP to the latest version (, to see if that added JDK 17 to the list and it did not. I dug around on this forum and elsewhere to try to find a solution or at least a guide to upgrade Java on an AMP instance and found reference to AdoptOpenJDK which is apparently the JDK package that AMP integrates? It appears AdoptOpenJDK only offers versions up to v16 so with that ruled out I found no reference to how to safely upgrade to JDK 17. (note: I also restarted the instance, AMP server, and VPS at every appropriate step)

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  • guy_davis
Mike posted this 21 November 2021

apt install openjdk-17-jre-headless should suffice - although you may have to upgrade to Debian 11 to get that package.