The Javadocs for FXMLLoader and the FXML annotation are painfully minimal. For FXMLLoader, none of the parameters for method or constructor calls are documented, and there is no lifecycle documentation. The FXML annotation basically has no documentation at all; it should document how the annotation relates to loaded FXML files, etc.

As an example, I discovered simply by trial and error that I could inject the FXML loader's resources into the controller with the following annotation:

@FXML
private ResourceBundle resources ;

It seems (from trial and error) that the variable name has to be "resources", though this isn't documented anywhere. It should be both in the set/getResources documentation in FXMLLoader and in the documentation for @FXML. (The latter should document all supported uses of the annotation.)

Any uses of FXMLLoader and controller classes beyond the very simplest are quite difficult without explicit documentation. While the "Introduction to FXML" document provides some detail, it is incomplete; additionally including pertinent information in the javadocs is friendlier to IDEs.