Run this snippet and see an NPE happening:



import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Menu;
import javafx.scene.control.MenuBar;
import javafx.scene.control.MenuItem;
import javafx.scene.layout.BorderPane;
import javafx.stage.Stage;

public class SimpleApp extends Application {

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

@Override
public void start(Stage primaryStage) throws Exception {
BorderPane p = new BorderPane();
final MenuBar bar = new MenuBar();
final Menu m = new Menu("File");
final MenuItem item = new MenuItem("Hello");
m.getItems().add(item);
bar.getMenus().add(m);
p.setTop(bar);
Button remove = new Button("Remove");
remove.setOnAction(new EventHandler<ActionEvent>() {

@Override
public void handle(ActionEvent event) {
bar.getMenus().remove(m);
m.getItems().remove(item);
}
});
p.setCenter(remove);

primaryStage.setScene(new Scene(p,300,300));
primaryStage.show();
}

}