JavaFX Circle create pie chart

import java.util.ArrayList;

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.layout.Pane;
import javafx.scene.paint.Color;
import javafx.scene.shape.Arc;
import javafx.scene.shape.ArcType;
import javafx.scene.shape.Circle;
import javafx.scene.shape.Shape;
import javafx.scene.text.Text;
import javafx.stage.Stage;

public class Main extends Application {

  private static double[] percent = new double[] { 0.20, 0.10, 0.30, 0.40 };
  private static String[] titles = new String[] { 
      "CSS -- " + String.format("%d%s", (int) (100 * percent[0]), "%"),
      "HTML -- " + String.format("%d%s", (int) (100 * percent[1]), "%"),
      "Java -- " + String.format("%d%s", (int) (100 * percent[2]), "%"),
      "SQL -- " + String.format("%d%s", (int) (100 * percent[3]), "%") };
  private static Color[] colors = new Color[] { Color.RED, Color.BLUE, Color.GREEN, Color.ORANGE };

  private static double RADIUS = 100;
  private static double CENTER_X = 200;
  private static double CENTER_Y = 200;

  @Override/*from   w  w w . j  a v  a  2s .  c  o m*/
  public void start(Stage primaryStage) {

    Pane pane = new Pane();
    ArrayList<Shape> shapes = new ArrayList<>();

    Circle c = new Circle(CENTER_X, CENTER_Y, RADIUS, Color.TRANSPARENT);
    c.setStroke(Color.BLACK);
    shapes.add(c);
    double angle = 0;
    for (int i = 0; i < titles.length; i++) {

      double length = percent[i] * 100 * 3.6;
      Arc arc = new Arc(CENTER_X, CENTER_Y, RADIUS, RADIUS, angle, length);
      arc.setFill(colors[i]);
      arc.setType(ArcType.ROUND);
      shapes.add(arc);

      double x = CENTER_X + RADIUS * Math.cos(Math.toRadians(angle * -1 - (length / 2)));
      double y = CENTER_Y + RADIUS * Math.sin(Math.toRadians(angle * -1 - (length / 2)));
      if (y > CENTER_Y) {
        y -= RADIUS / 2;
        x -= RADIUS / 2;
      }
      Text text = new Text(x, y, titles[i]);
      shapes.add(text);

      angle += length;
    }

    pane.getChildren().addAll(shapes);
    primaryStage.setScene(new Scene(pane, 400, 400));
    primaryStage.setTitle("Pie Chart");
    primaryStage.show();
  }

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

}