javafx progressbar

import javafx.application.Application;
import javafx.beans.value.ChangeListener;
import javafx.beans.value.ObservableValue;
import javafx.concurrent.Task;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.geometry.Pos;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.control.ProgressBar;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.HBox;
import javafx.scene.paint.Color;
import javafx.stage.Stage;

public class Main extends Application {
Task copyWorker;
public static void main(String[] args) {
Application.launch(args);
}
@Override
public void start(Stage primaryStage) {
primaryStage.setTitle("Background Processes");
Group root = new Group();
Scene scene = new Scene(root, 330, 120, Color.WHITE);

BorderPane mainPane = new BorderPane();
root.getChildren().add(mainPane);

final Label label = new Label("Files Transfer:");
final ProgressBar progressBar = new ProgressBar(0);

final HBox hb = new HBox();
hb.setSpacing(5);
hb.setAlignment(Pos.CENTER);
hb.getChildren().addAll(label, progressBar);
mainPane.setTop(hb);

final Button startButton = new Button("Start");
final Button cancelButton = new Button("Cancel");
final HBox hb2 = new HBox();
hb2.setSpacing(5);
hb2.setAlignment(Pos.CENTER);
hb2.getChildren().addAll(startButton, cancelButton);
mainPane.setBottom(hb2);

startButton.setOnAction(new EventHandler<ActionEvent>() {

public void handle(ActionEvent event) {
startButton.setDisable(true);
progressBar.setProgress(0);
cancelButton.setDisable(false);
copyWorker = createWorker();

progressBar.progressProperty().unbind();
progressBar.progressProperty().bind(copyWorker.progressProperty());

copyWorker.messageProperty().addListener(new ChangeListener<String>() {
public void changed(ObservableValue<? extends String> observable, String oldValue, String newValue) {
System.out.println(newValue);
}
});

new Thread(copyWorker).start();
}
});
cancelButton.setOnAction(new EventHandler<ActionEvent>() {
public void handle(ActionEvent event) {
startButton.setDisable(false);
cancelButton.setDisable(true);
copyWorker.cancel(true);
progressBar.progressProperty().unbind();
progressBar.setProgress(0);
System.out.println("cancelled.");
}
});
primaryStage.setScene(scene);
primaryStage.show();
}

public Task createWorker() {
return new Task() {
@Override
protected Object call() throws Exception {
for (int i = 0; i < 10; i++) {
Thread.sleep(2000);
updateMessage("2000 milliseconds");
updateProgress(i + 1, 10);
}
return true;
}
};
}
}