JavaFX 2.0: Implement Fade In/Fade Out animation

This exercise implement OnMouseEntered and OnMouseExited EventHandler, to apply Fade In and Fade Out animation on a button when mouse move in and move out the scene.

package javafx_fadeinout;

import javafx.animation.FadeTransition;
import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.input.MouseEvent;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;
import javafx.util.Duration;

/**
 *
 * @web http://java-buddy.blogspot.com/
 */
public class JavaFX_FadeInOut extends Application {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        launch(args);
    }
    
    @Override
    public void start(Stage primaryStage) {
        primaryStage.setTitle("http://java-buddy.blogspot.com/");
        final Button btn = new Button();
        btn.setText("Say 'Hello World'");
        btn.setOnAction(new EventHandler<ActionEvent>() {

            @Override
            public void handle(ActionEvent event) {
                System.out.println("Hello World!");
            }
        });
        
        StackPane root = new StackPane();
        root.getChildren().add(btn);
        Scene scene = new Scene(root, 300, 250);
        
        scene.setOnMouseEntered(new EventHandler<MouseEvent>(){

            public void handle(MouseEvent mouseEvent){
                FadeTransition fadeTransition 
                        = new FadeTransition(Duration.millis(500), btn);
                fadeTransition.setFromValue(0.0);
                fadeTransition.setToValue(1.0);
                fadeTransition.play();
            }
        });
        
        scene.setOnMouseExited(new EventHandler<MouseEvent>(){

            public void handle(MouseEvent mouseEvent){
                FadeTransition fadeTransition 
                        = new FadeTransition(Duration.millis(500), btn);
                fadeTransition.setFromValue(1.0);
                fadeTransition.setToValue(0.0);
                fadeTransition.play();
            }
        });
        
        primaryStage.setScene(scene);
        primaryStage.show();
    }
}