Jarock first run

A beginner-friendly sequence for taking a fresh Jarock download to a correctly configured server.

This is the compact website edition. The complete first-run guide contains the full troubleshooting table and translations.

1. Before starting

Use a 64-bit Windows installation and install a 64-bit Java 25 or newer JDK. With Eclipse Temurin, enable Set JAVA_HOME variable during installation, then reopen Command Prompt.
Extract the complete repository into any writable folder. Paths containing spaces are supported.
Do not double-click server/server.jar; always use start-server.bat from the repository root.
Make sure the computer has enough RAM, disk space, and Internet access for the first download.

2. Start the launcher

Double-click start-server.bat. Jarock resolves its own folder, checks the path, Windows long-path support, Java, templates, and settings in scripts/server-launch-settings.ini.

If Java 25 is missing and the bundled installers are present, Jarock launches prerequisites/jre-8-windows-x64.exe first and the Temurin JDK 25 MSI second. Accept each Windows UAC prompt and let both installers finish. Java 8 is a legacy prerequisite; Java 25 runs Minecraft.

Jarock never opens router ports, changes firewall rules, or configures port forwarding.

3. Choose a loader

On a fresh setup, choose one loader:

Choice	When to use it
Fabric	Recommended first choice for the supplied optimization, redstone, Geyser, Floodgate, and technical mods.
NeoForge	Fallback when a required mod is not available for Fabric.
Forge	Not installed silently while an official, verified Minecraft 26.2 server build is unavailable.

Jarock downloads and verifies the selected loader and its matching server-side manifest. Never mix Fabric and NeoForge files. If you change loader later, back up the world and run clean-server-runtime.bat first.

4. Configure optional settings

The first-run flow can open parameter-manager.bat in a separate window. It shows current values on the right and editable options on the left. You can configure RAM, GUI or console mode, the garbage collector profile, Java environment setup, online-mode, the ready banner, and the read-only startup update check.

Choose Save and exit or Save and start to keep changes. Choose Exit without saving to cancel without changing existing settings. The default is online-mode=true.

Important: do not set online-mode=false before the first successful startup. Let Minecraft create its initial files with online-mode=true. Only change it later for a private, trusted setup when you understand the authentication risks.

5. Accept the Minecraft EULA

The first bootstrap creates server/eula.txt and normally stops. Read the Minecraft EULA. If you agree, change eula=false to eula=true, save the file, and run start-server.bat again. Jarock never accepts the EULA for you.

6. Let the first server startup finish

Run the launcher again. Let it download and verify the loader, mods, and Geyser/Floodgate configuration, then wait while Minecraft generates the world. When Geyser is installed, the optional ready banner appears only after Geyser has started.

If a world-generation error occurs, stop safely and inspect server/logs/latest.log and server/crash-reports/. Do not repeatedly restart or delete a world before making a backup.

7. Stop safely

Type stop in the server console. Do not close the window immediately. Wait until Minecraft finishes saving and Jarock prints:

CLEAN SHUTDOWN COMPLETE
SAFE TO CLOSE

Only then close the window. Force-closing while the world is being saved can leave level.dat or world-generation data incomplete and may appear as world corruption.

After the first run

Keep online-mode=true unless this is a private, trusted test server.
Back up the world before changing loaders, mods, or important settings.
Complete TODO.md and read the network guide before making the server public.
If the startup update check is enabled, Jarock asks Download and install it now? (y/N) when a newer release is found. Choose y to install the verified package matching the installed CLI/TUI and Full/Lite edition, or N/Enter to continue with the current version; it never updates silently. Existing installations keep their Java prerequisites.
Keep generated worlds, logs, libraries, downloaded jars, keys, and local settings private.

For the full architecture explanation, read How does Jarock work?.