Browsing the server.jar code
Learn how to patch the server.jar and browse the source code.
The patcher allows you to more easily prepare an environment for exploring the Hytale Server without publishing the decompiled code.
Setup
-
Clone the patcher
git clone https://github.com/HytaleModding/patcher.git, and enter the directory.cd patcher -
Create a Python virtual environment in the
.venvfolder. The command for this varies by platform but it is probably one of these:python -m venv .venvpython3 -m venv .venv(Linux)py -3.13 -m venv .venv(Windows)
In the last one, specifying the version is recommended if you have multiple Pythons installed.
-
Activate the virtual environment:
- Windows:
".venv\Scripts\activate"(including the quotes) - Linux/Mac:
source .venv/bin/activate - From now on, you are running python commands from inside the venv, hence you must use
pythoninstead ofpyorpython3to invoke python.
- Windows:
-
Inside the venv, you have to install the dependencies
pip install -r requirements.txt
-
Install these dependencies and ensure they are on PATH:
gitjavayou need JDK 25 or newerjar(comes with JDK inside the bin folder)mvn
Usage
Put your HytaleServer.jar in the same root directory of this repo or specify an environment variable HYTALESERVER_JAR_PATH with the path to your HytaleServer.jar
Then run this:
python run.py setupIt will
- copy the HytaleServer.jar into
work/download- (on Windows) fix
META-INF/licensename collision
- (on Windows) fix
- decompile it using Fernflower and save the output to
work/decompile - set up a Maven project in
hytale-serverwith the decompiled code
You can then open the hytale-server folder in your favorite IDE and begin exploring the code. For IntelliJ IDEA,
you must first set up the SDK. After opening the project (you can open the pom.xml file, IDEA will prompt you to open
the entire project) press Ctrl+Alt+Shift+S and under Project configure SDK and Language level to 25.
If IDEA does not offer an option to run the main file, right-click the src folder -> Mark Directory As -> Sources Root
then reload the maven project:

It is located in the "m" icon on the right side:

If you don't see it, enable it under View -> Tool Windows -> Maven.

This decompiled code is likely broken. But it is somewhat usable for exploration. Try Ctrl+Shift+F and search PacketAdapters