mainClass

package sample;

import javafx.application.Application;
import javafx.application.Platform;
import javafx.fxml.FXMLLoader;
import javafx.scene.Scene;
import javafx.scene.control.*;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;
import java.util.Optional;


public class Main extends Application {


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

	@Override
	public void start(Stage primaryStage) throws Exception {
		FXMLLoader loader = new
				FXMLLoader(getClass().getResource("sample.fxml"));
		VBox rootNode = loader.load();

		Scene scene = new Scene(rootNode);

		primaryStage.setScene(scene);
		primaryStage.setTitle("Temperature converter tool");
		MenuBar menuBar=createmenu();
		rootNode.getChildren().add(0,menuBar);
		primaryStage.show();
	}

	private MenuBar createmenu(){
		Menu filemenu=new Menu("File");
		MenuItem newMenuItems=new MenuItem("New");

		MenuItem exitMenuItems=new MenuItem("Exit");
		SeparatorMenuItem separatorMenuItems=new SeparatorMenuItem();
		filemenu.getItems().addAll(newMenuItems, separatorMenuItems,exitMenuItems);
		exitMenuItems.setOnAction(event ->{
			Platform.exit();
			System.exit(0);
		});
		newMenuItems.setOnAction(event ->System.out.println("new menu item is clicked"));



		Menu help=new Menu("Help");
		MenuItem about=new MenuItem("about developer");
		help.getItems().addAll(about);
		about.setOnAction(event -> aboutapp());

		MenuBar menuBar=new MenuBar();
		menuBar.getMenus().addAll(filemenu,help);
			return menuBar;
	}

	private void aboutapp() {
		Alert alertDialog=new Alert(Alert.AlertType.INFORMATION);
		alertDialog.setTitle("MY FIRST DESKTOP APP");
		alertDialog.setHeaderText("LEARNING JAVA FX");
		alertDialog.setContentText("(DEVELOPER---> SONU KUMAR KUSHWAHA)This Is My First Desktop Application ,As I Am A Beginner,Soon I Will Be An Expert In Java fx ");
		ButtonType yb=new ButtonType("YES");
		ButtonType nb=new ButtonType("NO");
		alertDialog.getButtonTypes().setAll(yb,nb);

			Optional<ButtonType> ClickedBtn=alertDialog.showAndWait();
		if(ClickedBtn.isPresent()  && ClickedBtn.get()==yb){
			System.out.println("yes button clicked");
		}else{
			System.out.println("no button clicked");
		}

	}




}