import javafx.application.Application;
import javafx.application.Platform;
import javafx.scene.Scene;
import javafx.scene.control.*;
import javafx.scene.layout.BorderPane;
import javafx.stage.Stage;

public class MenuBarTestApp extends Application {

    @Override
    public void start(Stage primaryStage) {
        // Create menu bar
        MenuBar menuBar = new MenuBar();

        // Create "File" menu
        Menu fileMenu = new Menu("File");
        MenuItem newItem = new MenuItem("New");
        MenuItem openItem = new MenuItem("Open");
        MenuItem exitItem = new MenuItem("Exit");
        exitItem.setOnAction(e -> primaryStage.close()); // Close app

        fileMenu.getItems().addAll(newItem, openItem, new SeparatorMenuItem(), exitItem);

        // Create "Edit" menu
        Menu editMenu = new Menu("Edit");
        MenuItem cutItem = new MenuItem("Cut");
        MenuItem copyItem = new MenuItem("Copy");
        MenuItem pasteItem = new MenuItem("Paste");

        editMenu.getItems().addAll(cutItem, copyItem, pasteItem);

        // Create "Help" menu
        Menu helpMenu = new Menu("Help");
        MenuItem aboutItem = new MenuItem("About");
        aboutItem.setOnAction(e -> showAboutDialog());

        helpMenu.getItems().add(aboutItem);

        // Add menus to the menu bar
        menuBar.getMenus().addAll(fileMenu, editMenu, helpMenu);

        // Create root layout
        BorderPane root = new BorderPane();
        root.setTop(menuBar);

        Button button = new Button("Toggle FullScreen");
        button.setOnAction(e -> primaryStage.setFullScreen(!primaryStage.isFullScreen()));
        root.setCenter(button);

        // Set scene
        Scene scene = new Scene(root, 500, 400);
        primaryStage.setTitle("JavaFX Menu Bar Example");
        primaryStage.setScene(scene);
	    primaryStage.show();
    }

    private void showAboutDialog() {
        Alert alert = new Alert(Alert.AlertType.INFORMATION);
        alert.setTitle("About");
        alert.setHeaderText("JavaFX Menu Bar Example");
        alert.setContentText("This is a simple JavaFX application with a menu bar.");
        alert.showAndWait();
    }

    public static void main(String[] args) {
        launch(MenuBarTestApp.class, args);
    }
}