So this worked in the example from javafx when My pc had jdk 1.7.0 so this may be the new version of FX in java8 however;
I get a nice stack-trace
jf
In Run >> Edit Configurations
Add this line to VM Options:
--module-path /path/to/JavaFX/lib --add-modules=javafx.controls,javafx.fxml
this worked for me after tones of search