How to reproduce the issue:

mvn package -P openjfx-desktop

If on Linux for example, let's install the generated debian package:

sudo dpkg -i webfx-example-application-openjfx/target/javapackager/webfx-example_1.0.0.deb

After successful installation, trying to run it:

webfx-example

It doesn't find the main class:

Error: Could not find or load main class dev.webfx.platform.shared.services.boot.ApplicationBooter Caused by: java.lang.ClassNotFoundException: dev.webfx.platform.shared.services.boot.ApplicationBooter

To generate the fat jar:

mvn package -P openjfx-fatjar

Then starting the application with the fat jar:

java -jar webfx-example-application-openjfx/target/webfx-example-application-openjfx-1.0.0-fat.jar

It works (it's just a simple JavaFX application saying "HelloWorld").