Startup Issue with Minecraft - server startup not working using AMP

System Information

Field Value
Operating System Windows - Windows 10 Home on x86_64
Product AMP ‘Phobos’ v2.6.0.10 (Mainline)
Virtualization None
Application Minecraft
Module MinecraftModule
Running in Container No
Current State Failed

Problem Description

Issue

I didn’t change any startup settings i just tried to start my server and it did not work.
Exception in thread “main” java.lang.UnsupportedClassVersionError: net/minecraft/bundler/Main has been compiled by a more recent version of the Java Runtime (class file version 65.0), this version of the Java Runtime only recognizes class file versions up to 52.0
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(Unknown Source)
at java.security.SecureClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.access$100(Unknown Source)
at java.net.URLClassLoader$1.run(Unknown Source)
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.launcher.LauncherHelper.checkAndLoadMain(Unknown Source)

Reproduction Steps

  • created server but did not change it to different type, i kept it on Official
  • customized settings but did not change anything to do with boot
  • server does not start

wrong java version selected

I have it set to auto and there are no other options how do I get the correct version of Java?

Not the Server JAR, the Java Version

You have selected Java 8 and you need Java 21

how do I get java 21 for my server?

Grep the msi and install it. Restart the instance after installing and see if Java 21 is available as selection. If not, restart the whole host. After a full restart, you should be able to select Java 21 in the instance.

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