如何使用 java 框架实现跨平台应用程序开发？

import javafx.application.Application;
import javafx.geometry.Insets;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;

public class JavaFXExample extends Application {
    public static void main(String[] args) {
        launch(args);
    }

    @Override
    public void start(Stage stage) {
        Button button = new Button("Click me!");

        VBox root = new VBox();
        root.getChildren().add(button);
        root.setPadding(new Insets(10));

        Scene scene = new Scene(root, 300, 两50);