JavaFX example: open new Window and exit all when primary window close

JavaFX example to open new Window, and exit all when primary window close.

package javafxwindow;

import javafx.application.Application;
import javafx.application.Platform;
import javafx.event.ActionEvent;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;

/**
 *
 * @web http://java-buddy.blogspot.com/
 */
public class JavaFXWindow extends Application {
    
    @Override
    public void start(Stage primaryStage) {
        Button btn = new Button();
        btn.setText("Open a New Window");
        btn.setOnAction((ActionEvent event) -> {
            Label secondLabel = new Label("Hello");
            
            StackPane secondaryLayout = new StackPane();
            secondaryLayout.getChildren().add(secondLabel);
            
            Scene secondScene = new Scene(secondaryLayout, 200, 100);
            
            Stage secondStage = new Stage();
            secondStage.setTitle("New Stage");
            secondStage.setScene(secondScene);
            
            secondStage.show();

        });
         
        StackPane root = new StackPane();
        root.getChildren().add(btn);
         
        Scene scene = new Scene(root, 300, 250);
         
        primaryStage.setTitle("java-buddy.blogspot.com");
        primaryStage.setScene(scene);
        primaryStage.show();
        
        primaryStage.setOnCloseRequest(e -> Platform.exit());

    }

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