Articles on: Game :: Minecraft Java

How to Install a Custom Server Jar on Your Minecraft Server

Want to run a custom version of Minecraft, a modded jar, or your own server build?

Serverwave makes it easy to upload and use a custom server jar, giving you full control over your setup.

What Is a Custom Server Jar?

A server jar is the main file that runs your Minecraft server — examples include:

paper.jar for Paper servers
forge-1.20.1.jar for Forge modded servers
fabric-server-launch.jar for Fabric
Or your own custom-compiled jar

By uploading a custom jar, you can:

Run custom server types or forks (e.g. Purpur, Mohist, Arclight)
Use specific mod or plugin versions
Host experimental builds or private versions

What You’ll Need:

Your custom .jar file ready (from a trusted source).
Access to your Serverwave Control Panel.
SFTP or File Manager access.
Your server is fully stopped before changing jars.

Need help connecting via SFTP? See our guide: How to Use SFTP on Serverwave

Stop Your Server

In the panel, click Stop and wait until the server status shows Offline.

Upload Your Custom Jar

Option 1: Via File Manager: Go to File Manager → Upload, select your .jar, and place it in the root directory (same folder as server.properties).

Option 2: SFTP (Alternative): Connect via SFTP → Upload the .jar to the root folder.

Don’t put it inside subfolders like /plugins/ or /mods/.

Rename

The server jar must be called server.jar otherwise the server will not start.

Start Your Server - Click Start.

If the jar is configured correctly, the console will show your custom server running.

Troubleshooting

❌ “Unable to access jarfile”

→ The filename you uploaded doesn’t have the name server.jar.

Double-check the name (including .jar) and that the file is in the root directory.

🕹 “Server crashes immediately”

→ Your jar may be missing dependencies or requires more RAM.

Check the console logs for details or verify the jar’s compatibility.

⚠️ File won’t upload

→ If your file is large, try uploading via SFTP instead of the File Manager.

💡 Serverwave Tip:

You can keep multiple jars uploaded (like paper.jar, purpur.jar, and forge.jar) — just update the name to server.jar to switch between them anytime.

Updated on: 17/10/2025

Was this article helpful?

Thank you!