Minecraft 1.20.5+ needs Java 21+

[jayonthenet]

Newer MC versions won't run because of Java 19 being used as the baseline. Tested with -e 1.20.5 and -e 1.20.6. Leads to the following error during container start:

ViaVersion is up to date
Starting Minecraft server...
Starting org.bukkit.craftbukkit.Main
Exception in thread "ServerMain" java.lang.UnsupportedClassVersionError: org/bukkit/craftbukkit/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 63.0
	at java.base/java.lang.ClassLoader.defineClass1(Native Method)
	at java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:1013)
	at java.base/java.security.SecureClassLoader.defineClass(SecureClassLoader.java:150)
	at java.base/java.net.URLClassLoader.defineClass(URLClassLoader.java:524)
	at java.base/java.net.URLClassLoader$1.run(URLClassLoader.java:427)
	at java.base/java.net.URLClassLoader$1.run(URLClassLoader.java:421)
	at java.base/java.security.AccessController.doPrivileged(AccessController.java:712)
	at java.base/java.net.URLClassLoader.findClass(URLClassLoader.java:420)
	at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:588)
	at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521)
	at java.base/java.lang.Class.forName0(Native Method)
	at java.base/java.lang.Class.forName(Class.java:495)
	at java.base/java.lang.Class.forName(Class.java:474)
	at io.papermc.paperclip.Paperclip.lambda$main$0(Paperclip.java:38)
	at java.base/java.lang.Thread.run(Thread.java:1589)

[NemoN]

see pull request https://github.com/TheRemote/Legendary-Java-Minecraft-Geyser-Floodgate/pull/32

[jayonthenet]

Added a PR that updates MC to 1.20.6 and Java to 21 - see #33

[johnholton0]

I'm experiencing this issue as well with running the container and getting my kids' tablets running Bedrock to connect. Can't force the container to run newer versions because of the Java 21 issue.

[jayonthenet]

Seems like this is solved now. Will close this issue.