How to make a Minecraft server (Java Edition 26.3)

1Install Java 25

Minecraft 26.1 and newer need Java 25: Mojang's file for 26.3 asks for it by name, and an older Java stops the server at once. Minecraft 1.21 needs Java 21.

• Ubuntu 24.04: sudo apt install openjdk-25-jre-headless. On 29 Sep the package was 25.0.4.1.
• Windows and macOS: Temurin 25 from Adoptium, the same Java we ran our server on.
• To check: java -version should begin openjdk version "25.

2Download the server jar

minecraft.net's server page links the newest version's jar and gives the command to run it: java -Xmx4G -Xms4G -jar, the file, and nogui. Mojang's version list has the same jar for each version, with its SHA-1. For 26.3 it's 62 MB, so you can download and check it from a terminal:

# An empty folder for the server
mkdir minecraft-server && cd minecraft-server
curl -o server.jar https://piston-data.mojang.com/v1/objects/33680f5f2ac32864d6d7cf5e56a705fdb3e05f4c/server.jar
sha1sum server.jar   # 33680f5f2ac32864d6d7cf5e56a705fdb3e05f4c
java -Xmx2G -jar server.jar nogui
# It stops at the EULA the first time
sed -i 's/eula=false/eula=true/' eula.txt
java -Xmx2G -jar server.jar nogui

# Run it in tmux, so it keeps going when you log out
tmux new -s minecraft
java -Xmx2G -jar server.jar nogui
# Ctrl+B, then D, leaves it running. To come back:
tmux attach -t minecraft
# In the server's console, stop saves the world and quits
stop

3Start it, and accept the EULA

1. 1

   Run it once

   Ours took 4 seconds: it unpacked about 70 MB of libraries next to the jar, wrote eula.txt and server.properties, and stopped with You need to agree to the EULA in order to run the server.

2. 2

   Accept the EULA

   Open eula.txt, change eula=false to eula=true, and save it. It's Minecraft's licence, and the server won't start without it.

3. 3

   Run it again

   The log says Starting Minecraft server on *:25565, then Done. Ours was ready 7 seconds after it started, with a new world, and used about 600 MB of memory with nobody on.

The EULA stop has its own page, with the ways eula.txt goes wrong. Type stop in the console to save the world and quit.

4Let your friends in

Minecraft 26.3's server.properties starts with white-list=true, where 26.2's and 26.1's started with false. So a new server lets in only the players you add, and anyone else sees the game's message:

The server looks each name up with Mojang, so spell it as it is in the game. Once our test player's name was on the list, it got in.

5The settings worth a look

These are 26.3's own defaults in server.properties. Change them with the server stopped, or use the server.properties editor.

PvP isn't in the file any more: in 26.3 it's a game rule, and gamerule pvp answered Game rule pvp is currently set to true.

6Let players reach it

• On the same network, players add the computer's local address, like 192.168.1.20. The game shows the server's version and player count when it's reachable: ours showed 26.3, 0 of 20.
• From anywhere else, open TCP port 25565 in the computer's firewall and forward it on your router: port forwarding, step by step. On a VPS there's no router, just the firewall.
• A server on your PC runs only while the PC is on. Friends can't play while it's off; a VPS stays on.

7Back up the world

The world is the world folder. Stop the server first, so nothing is written while you copy, then copy it somewhere else, like cp -r world world-backup. What a damaged world does shows how a backup brings one back.

8When it won't start

• Error: LinkageError occurred while loading main class, then UnsupportedClassVersionError and class file version 69.0: 26.3 was started on an older Java, Java 21 in our test. Install Java 25.
• Error: Unable to access jarfile: Java can't find the file you named. The fix.
• FAILED TO BIND TO PORT!: something else has port 25565. The fix.

Every error we've tested, with its fix, is on the errors page.

9The one-click way

Playkeeper does all of this on a VPS you rent: Java, the server, the port and the allowlist. Install it with one command:

• New server creates one on the Java its version needs, and keeps it on.
• Invite links on the Players tab put a friend on the allowlist when they type their Minecraft name, right away or once you say yes.
• Schedules back up each server on the days and times you choose, and the World tab restores a backup.