Description of issue

When I start net.minecraft.server.Main for Java 26.1.2 running on Ubuntu 24.04.4 LTS Cinnamon Version 6.0.4, I get the following new warning messages in the terminal that were not shown in previous versions 1.21.11 or 1.21.10 of launching the server.jar. No mods are in use.

WARNING: A restricted method in java.lang.System has been called

WARNING: java.lang.System: :load has been called by com.sun.jna.Native in an unnamed module (file: /home/myusername/libraries/net/java/dev/jna/jna/5.17.0/jna-5.17.0.jar)

WARNING: Use --enable-native-access=ALL-UNNAMED to avoid a warning for callers in this module

WARNING: Restricted methods will be blocked in a future release unless native access is enabled

WARNING: A terminally deprecated method in sun.misc.Unsafe has been called

WARNING: sun.misc.Unsafe: :objectFieldOffset has been called by org.joml.MemUtil$MemUtilUnsafe (file: /home/myusername/libraries/org/joml/joml/1.10.8/joml-1.10.8.jar)

WARNING: Please consider reporting this to the maintainers of class org.joml.MemUtil$MemUtilUnsafe

WARNING: sun.misc.Unsafe: :objectFieldOffset will be removed in a future release

Steps to reproduce

I use a standard shortcut saved as start_server.sh to launch the server.jar file in between occasions when I stop the server to take a backup copy.

#!/bin/bash

cd ~/26.1.2-minecraft-server

java -Xms512M -Xmx1G -jar server.jar

Expected result

A normal launch with the server GUI showing the status, log, and chat, without warning messages.

Actual result

The error message appears in the terminal each time I launch 26.1.2’s server.jar, before the server GUI opens.

It proceeds to load the world files like normal and can be joined inside my home network from a Windows 11 device running Java edition 26.1.2. The only thing that prompted me that something was wrong was when players outside my home network lost the ability to connect and I turned on a monitor to the server machine to reboot for OS updates and relaunch the server. Their ability to connect may or may not be related to the warning messages I’m reporting, but we haven’t had connectivity issues for whitelisted players since I first set up the server with Java version 1.21.10.