How to reload the screen when changing languages in JavaFX 2?

Question

I'm beginner with javaFX and i need to change language of the screen. but i have no idea how to reload the screen when the language was changed. The application have a button where have the language available. I want just refresh screen when the user change language.
Here is the start method to show the stage.
    @Override
    public void start(Stage stage) throws Exception
        this.stage = stage;
        Locale locale = Locale.getDefault();
        ResourceBundle rb = ResourceBundle.getBundle("resources/Label",locale);
        loader = new FXMLLoader(getClass().getResource("FXMLDocument.fxml"),rb);
        root = (Parent)loader.load();
        FXMLDocumentController controller = (FXMLDocumentController) loader.getController();
        controller.setMain(this);
        scene = new Scene(root);
        stage.setScene(scene);
        stage.show();
here is the function to change the language(in the same class with start function),the rb is the new ResourceBundle:
    public void refresh(ResourceBundle rb)
          //change the language here
1. I don't want to use the resourceBundle to get value in resource file and set label in scene one by one.like following:
this.btnLabel.setText(rb.getString(key.test));
2. I don't want to reload the scene,like following:
    public void refresh(ResourceBundle rb)
         try
            loader = new FXMLLoader(getClass().getResource("FXMLDocument.fxml"),rb);
            root = (Parent)loader.load();
            scene.setRoot(root);
            FXMLDocumentController controller = (FXMLDocumentController) loader.getController();
            controller.setMain(this);
        catch(Exception err)
            err.printStackTrace();
So do we have a solution to just set the resourceBundle and reload the scene easier?
Thanks and best regards!

Answer 1

Your option 2 (reload the FXML for the scene using the new resource bundle as a parameter), is the way this would normally be done and what I would recommend.
Failing that, you could use option 1 of individually resetting the label text of labeled items (I don't really recommend this).
Why don't you want to use option 2?
Perhaps it is because there is some internal state of the UI which differs from the initial state when the the UI is first loaded (e.g. user has typed text in a text field and you want to preserve that).  If that's the case you will need to either go with your option 1 of individually resetting the label text of labeled items, or implement something which preserves the UI state and user data by saving it in memory or to disk, reloading the UI via the FXMLLoader (essentially your option 2), then restoring the UI state and user data to what it was before the language change.  Preserving and restoring the modified state seems complicated to me if you have a lot of state, so I wouldn't really advise this approach unless you really needed it.