SOLVED - See final update

Hey! My understanding is that the latest Minecraft update requires Java 25 for me to run it on my server. I've been browsing google, and reddit for about 45 minutes now, and I'm still currently having issues trying to update and would like some help, or troubleshooting tips.

I'm running a paper server through Crafty, on a headless Debian system.

When I attempt to start my server after updating the Jar, I get this message

"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"

I've checked the manual override in my Crafty config settings, but the highest available java version is 21.

I've attempted to update everything in my OS through the terminal.

I've run a fix command for any corrupted files.

But when I attempt to install the Java 25 package with any of these commands

sudo apt install openjdk-25-jre

# apt install openjdk-25-jdk

apt install temurin-25-jdk 

I get the message "Unable to locate package <whatever the name was I attempted to install>

My current understanding is that Java25 may not be in the repositories for the version of Debian I am currently running? I have a decent idea of what that means, but I'm not a Linux expert so I don't want to assume too much.

Is there any anybody who has run into/fixed this issue? Do you guys have any work around, or fixes for this issue? Or is this just completely not an option any longer without some sort of OS change? I'm just trying to play the latest version of Minecraft with some friends. Please let me know if you have questions, or need any more information that could help out. I really appreciate it.

Update - Progress

I was able to manually install Java 25. I found the .deb file on the oracle website for the version of Java that I wanted and ran this command, followed by the download link I found.

wget [https://download.oracle.com/java/25/latest/jdk-25_linux-x64_bin.deb]

sudo dpkg -i [jdk-25_linux-x64_bin.deb]

Then verified the install using this command

java -version

I am still having an issue though. I can't get my Crafty to show the latest version of Java installed so that I can override it before I start the server. I'll update if I find a fix!

Update 2 - Progress?

After I was unable to get my Crafty to show me Java version 25 in the list of overrides, I attempted to add a repository to my install.

I installed Adoptium and was able to successfully run

apt install temurin-25-jdk

to get the latest version that way, but I am still facing the issue of my Crafty not showing me any options for java versions above 21. I'm at a bit of a loss, but I'll continue to look into it and update as I go.

Update 3 - Solved

I don't know man. I just started giving up. I updated my Crafty from 4.4.4 to 4.4.11 (Stable) and had all of these issues even after updating my Java manually, adding Adoptium as a repo, etc. I checked through config options, and CraftyController documentation, I restarted Crafty several times. I went back and changed the crafty version to Latest instead (I guess in hindsight I should have done that the first time around? F me for seeing "Stable" and going with that). Long story short, that made Java 25 populate on my list of versions.

TLDR: Manually updated my java on debian. Added Adoptium repo and installed Java 25 JDK through that. Updated Crafty to the "Latest" option. Seems to be working fine now?

I really hope my several hours of research and struggle help save one of you some time. Thanks to all the guys who helped me out!