JavaFX Shadow effect

import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.effect.InnerShadow;
import javafx.scene.layout.FlowPane;
import javafx.scene.paint.Color;
import javafx.stage.Stage;

public class Main extends Application {

   boolean shadow = false;

   InnerShadow innerShadow = new InnerShadow(10.0, Color.RED);
   // Create four push buttons.
   private Button btn = new Button("Click to see effect");

   public static void main(String[] args) {
      launch(args);/* w w  w  .j a va  2 s.c om*/
   }

   public void start(Stage myStage) {
      myStage.setTitle("Effects Demo");
      FlowPane rootNode = new FlowPane(10, 10);
      rootNode.setAlignment(Pos.CENTER);
      Scene myScene = new Scene(rootNode, 300, 100);
      myStage.setScene(myScene);
      btn.setEffect(innerShadow);

      btn.setOnAction(new EventHandler<ActionEvent>() {
         public void handle(ActionEvent ae) {
            // Each time button is pressed, its shadow status is changed.
            shadow = !shadow;
            if (shadow) {
               btn.setEffect(innerShadow);
               btn.setText("Shadow on");
            } else {
               btn.setEffect(null);
               btn.setText("Shadow off");
            }
         }
      });

      // Add the label and buttons to the scene graph.
      rootNode.getChildren().addAll(btn);

      // Show the stage and its scene.
      myStage.show();
   }
}