JavaFX Circle bind to Scene

import javafx.application.Application;
import javafx.beans.binding.Bindings;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.shape.Circle;
import javafx.stage.Stage;

public class Main extends Application {
  public static void main(String[] args) {
    Application.launch(args);// www  .j  ava 2 s. co  m
  }

  @Override
  public void start(Stage stage) {
    Circle c = new Circle();
    Group root = new Group(c);
    Scene scene = new Scene(root, 100, 100);

    // Bind circle's centerX, centerY, and radius to scene's properties
    c.centerXProperty().bind(scene.widthProperty().divide(2));
    c.centerYProperty().bind(scene.heightProperty().divide(2));
    c.radiusProperty().bind(Bindings.min(scene.widthProperty(), scene.heightProperty()).divide(2));

    // Set the stage properties and make it visible
    stage.setTitle("A Centered Circle");
    stage.setScene(scene);
    stage.sizeToScene();
    stage.show();
  }
}