Aside from only loading and FXML, you may need to use other FXMLLoader functionality. In this case, you need to construct an object:
FXMLLoader loader = new FXMLLoader(getClass().getResource("FXMLDocument.fxml"));loader.load();FirstController controller = loader.getController();Parent root = loader.getRoot();
Due to an unfortunate name choice, there are several overridden load() methods in FXML and most of them are static. Make sure you are using non-static methods for calls from the instantiated FXMLLoader. See the following example:
FXMLLoader loader = new FXMLLoader();
loader.load(getClass().getResource("FXMLDocument.fxml")); // STATIC method!
FirstController controller = loader.getController(); // returns null ...
