JavaFX-Creating Alert Boxes

Alert box. Java______
import javafx.stage.*;
import javafx.scene.*;
import javafx.scene.layout.*;
import javafx.scene.control.*;
import javafx.geometry.*;

public class AlertBox {

    public static void display(String title, String message) {
        Stage window = new Stage();

        //Block events to other windows
        window.initModality(Modality.APPLICATION_MODAL);
        window.setTitle(title);
        window.setMinWidth(250);

        Label label = new Label();
        label.setText(message);
        Button closeButton = new Button("Close this window");
        closeButton.setOnAction(e -> window.close());

        VBox layout = new VBox(10);
        layout.getChildren().addAll(label, closeButton);
        layout.setAlignment(Pos.CENTER);

        //Display window and wait for it to be closed before returning
        Scene scene = new Scene(layout);
        window.setScene(scene);
        window.showAndWait();
    }

}

Main.java______
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;

public class Main extends Application {

    Stage window;
    Button button;

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

    @Override
    public void start(Stage primaryStage) {
        window = primaryStage;
        window.setTitle("thenewboston");
        button = new Button("Click Me");

        button.setOnAction(e -> AlertBox.display("Title of Window", "Wow this alert box is awesome!"));

        StackPane layout = new StackPane();
        layout.getChildren().add(button);
        Scene scene = new Scene(layout, 300, 250);
        window.setScene(scene);
        window.show();
    }

}