A *mildly stupid* problem and solution to patch legacy minecraft bukkit/spigot/paper jars

mcpatcher.md

Step 1: Get software

Get the original vanilla minecraft server.jar and get the paper.jar in the same version (e.g. 1.8.8). I recommend using this service but proceed with caution as it technically goes against ToS of MC: https://jars.vexyhost.com/

Step 2: Patching

Instead of letting paper try to download from aws we will redirect it to our server.jar

danlp6@danlp6fw:~/Downloads/paper\ Hi DanLP6 Sat, 21 Jun 2025 00:27:28 +0200 56.800°C :$ java -jar paper-1.8.8-443.jar 
Downloading original jar...
Error downloading original jar
java.net.UnknownHostException: s3.amazonaws.com
	at java.base/sun.nio.ch.NioSocketImpl.connect(Unknown Source)
	at java.base/java.net.SocksSocketImpl.connect(Unknown Source)
	at java.base/java.net.Socket.connect(Unknown Source)
	at java.base/sun.security.ssl.SSLSocketImpl.connect(Unknown Source)
	at java.base/sun.security.ssl.BaseSSLSocketImpl.connect(Unknown Source)
	at java.base/sun.net.NetworkClient.doConnect(Unknown Source)
	at java.base/sun.net.www.http.HttpClient.openServer(Unknown Source)
	at java.base/sun.net.www.http.HttpClient.openServer(Unknown Source)
	at java.base/sun.net.www.protocol.https.HttpsClient.<init>(Unknown Source)
	at java.base/sun.net.www.protocol.https.HttpsClient.New(Unknown Source)
	at java.base/sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.getNewHttpClient(Unknown Source)
	at java.base/sun.net.www.protocol.http.HttpURLConnection.plainConnect0(Unknown Source)
	at java.base/sun.net.www.protocol.http.HttpURLConnection.plainConnect(Unknown Source)
	at java.base/sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(Unknown Source)
	at java.base/sun.net.www.protocol.http.HttpURLConnection.getInputStream0(Unknown Source)
	at java.base/sun.net.www.protocol.http.HttpURLConnection.getInputStream(Unknown Source)
	at java.base/sun.net.www.protocol.https.HttpsURLConnectionImpl.getInputStream(Unknown Source)
	at java.base/java.net.URL.openStream(Unknown Source)
	at org.apache.commons.io.FileUtils.copyURLToFile(FileUtils.java:1460)
	at com.destroystokyo.paperclip.Paperclip.main(Paperclip.java:90)

Step 2 1/2

Change the filename of the original server.jar to minecraft_server.X.X.X.jar for 1.8.8 it would be: minecraft_server.1.8.8.jar

Step 2 2/2

Setup a basic python3 -m http.server -> it runs on http://localhost:8000

Step 3: Patch the paper.jar

• extract the paper.jar like any zip archive (you also could change the filename to paper.jar.zip)
• search for a file named patch.json and open it
• search for this: "sourceUrl":
• and replace with this: "sourceUrl":"http://localhost:8000/minecraft_server.X.X.X.jar" as I use 1.8.8 for me it is "sourceUrl":"http://localhost:8000/minecraft_server.1.8.8.jar"

Step 4 "recompile"

Just Zip the archive again and change the file extension to .jar

Step 5 First Run the jar

When running the Jar it will (while your python webserver is running) querry it and the python server should say something that a client connected.

Step 6 Stop the python server

Now to be clear you now don't need to run the server anymore the initial download is completet