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Table of contents

  1. Java Downloads
  2. Cannot find JavaFX or No Class Def Found Error
    1. OpenJDK 8 OpenJFX fix on Ubuntu
    2. OpenJDK 8 OpenJFX fix on Windows
    3. What about Java 11+?
      1. OpenJDK 11+ OpenJFX on Windows
  3. Double clicking ChunkyLauncher.jar doesn’t work on Windows?
  4. Batch script to launch (Windows)

As stated in Installation, Chunky requires Java 8 update 40 or later (with JavaFX) and it is recommended that you use the 64 bit Java version if you have a 64 bit OS.

Java Downloads

Oracle Java 8 (including JavaFX)

Cannot find JavaFX or No Class Def Found Error

Exception in thread "main" java.lang.NoClassDefFoundError: javafx/stage/Stage
        at se.llbit.chunky.launcher.ChunkyLauncher.firstTimeSetup(
        at se.llbit.chunky.launcher.ChunkyLauncher.main(
Caused by: java.lang.ClassNotFoundException: javafx.stage.Stage
        at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(
        at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(
        at java.base/java.lang.ClassLoader.loadClass(
        ... 2 more

JavaFX/OpenJFX are often the short straw and unfortunately Chunky needs them. Below are a few solutions depending on platform and Java version.

OpenJDK 8 OpenJFX fix on Ubuntu

Below is a script you can run on Ubuntu to obtain and retain a working OpenJFX. credit - UNuX#1985 - 11/07/2019

apt install openjdk-8-jre
mkdir -p /tmp/chunky-deps-tmp
cd /tmp/chunky-deps-tmp
dpkg -i *.deb
apt-mark hold openjfx libopenjfx-java libopenjfx-jni

OpenJDK 8 OpenJFX fix on Windows

On Windows, OpenJDK does not come with OpenJFX and is does not, at the time of writing, have an official source. Instead you will need to find a pre-compiled build though I would not recommend this.

What about Java 11+?

If you wish to run Chunky on Java 11+ you will need to ensure you have ChunkyLauncher v1.12.1, or later, in addtion to OpenJFX.

OpenJDK 11+ OpenJFX on Windows

  1. Install the OpenJDK of your choice.

  2. Download the OpenJFX Windows SDK from gluonhq, extract to C:\Program Files\openjfx with the folder structure seen below.

  1. Launch ChunkyLauncher.jar either by double clicking the .jar file or by using java -jar "path\to\chunkylauncher\chunkylauncher.jar"

  2. Inside ChunkyLauncher, under Advanced Settings, the Java options field should be auto-populated with --module-path and --add-modules which point towards the openjfx install location.


    --module-path "C:\Program Files\openjfx" --add-modules=javafx.controls,javafx.base,,javafx.fxml


If you get the following error: java.lang.LayerInstantiationException: Package jdk.internal.jimage in both module java.base and module jrt.fs, open C:\Program Files\openjfx\lib and delete jrt-fs.jar; However this issue typically occurs if you merge OpenJFX’s lib folder into your OpenJDK lib folder.

Double clicking ChunkyLauncher.jar doesn’t work on Windows?

A common issue with Java on Windows is that jar files may not be correctly associated with Java.

This can be fixed by either uninstalling and reinstalling Java or through using an application like Jarfix or through launching via CMD, ie java -jar "path\to\chunkylauncher\chunkylauncher.jar".

Batch script to launch (Windows)

Don’t want to have to type out commands each time you want to launch Chunky? Well in comes Batch scripts!

Create a .txt file and enter the following lines, adjusting them where necessary to match the commands you need, then save the file as a .bat file in the same directory as ChunkyLauncher.jar.

cd /d %~dp0
java -jar ChunkyLauncher.jar --launcher

You can then right click the .bat file and create a shortcut which can be place on the desktop, pinned to the taskbar, etc.

For more advanced scripts please see the section on Automation