How to convert a normal java project in intellij into a JavaFx project

Question

I am currently using a normal java project (gradle project) and want to convert this into a JavaFx project without having to reimport the existing sources into a new Javafx

Answer 1

So after lots of googling I finally found it out myself!

If you can create new Javafx projects in Intellijd and it works perfectly, but when you open a normal java application that happens to use javafx doesn't work, (because java just doesn't want to resolve the javafx references)

what works for me is this: You must add the "jre/lib/ext/jfxrt.jar" file to the module classpath that is located inside IDEA on my windows machine this is C:\Program Files\JetBrains\IntelliJ IDEA Community Edition 2018.3.3\jre64\lib\ext\jfxrt.jar.

And now it finally builds!