Openjfx ea: error on trying to access private fields

[fastegal]

below is a small app that comes up with a button: on click it wants
to access a private field (obviouly via reflection) in the button class.
Due to relaxed permission constraints, that works in all java versions 9/10
without additional configuration and also with openjdk for non-fx classes.

With the combination of openjdk10 + openjfx-ea (both downloaded from their
respective download pages at java.net) it throws an error at runtime  
on clicking:

Exception in thread "JavaFX Application Thread"
java.lang.reflect.InaccessibleObjectException:
Unable to make field private javafx.beans.property.BooleanProperty
javafx.scene.control.Button.defaultButton accessible:
module javafx.controls does not "opens javafx.scene.control" to  
unnamed module @b65246

Happens both from the command line (thanks Johan for the concise example,
easy to understand even for a command line hater like myself :) as  
from inside eclipse

Any idea what's wrong?


public class MinimalAccessFieldFX10Open extends Application {

    private Parent getContent() {
        Button button = new Button("something to click on");

        button.setOnAction(e -> {
            // okay
            Object def = invokeGetFieldValue(Button.class, button,  
"defaultButton");
            LOG.info("getting the private field: " + def);
        });
        BorderPane pane = new BorderPane(button);
        return pane;
    }

    @Override
    public void start(Stage primaryStage) throws Exception {
        primaryStage.setScene(new Scene(getContent(), 600, 400));
        primaryStage.show();
    }

    public static Object invokeGetFieldValue(Class<?> declaringClass,
            Object target, String name) {
        try {
            Field field = declaringClass.getDeclaredField(name);
            field.setAccessible(true);
            return field.get(target);
        } catch (NoSuchFieldException | SecurityException
                | IllegalArgumentException | IllegalAccessException e) {
            e.printStackTrace();
        }
        return null;
    }

    public static void main(String[] args) {
        launch(args);
    }

    @SuppressWarnings("unused")
    private static final Logger LOG = Logger
            .getLogger(MinimalAccessFieldFX10Open.class.getName());
}