Bind JavaFX ProgressBar.progressProperty() to DoubleProperty in Thread

It's JavaFX version of last example "Java CountDownLatch and Thread" with ProgressBars. It show how to bind ProgressBar.progressProperty() to DoubleProperty in Thread, and update the DoubleProperty in Thread; such that it update ProgressBar automatically.

package javafxexecutorservice;

import java.util.concurrent.CountDownLatch;
import java.util.logging.Level;
import java.util.logging.Logger;
import javafx.application.Application;
import javafx.beans.property.DoubleProperty;
import javafx.beans.property.SimpleDoubleProperty;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.ProgressBar;
import javafx.scene.layout.StackPane;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;

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

    @Override
    public void start(Stage primaryStage) {
        
        CountDownLatch countDownLatch1 = new CountDownLatch(5);
        CountThread countThread1 = new CountThread("A", countDownLatch1, 5);
        ProgressBar progressBar1 = new ProgressBar();
        progressBar1.progressProperty().bind(countThread1.processProperty);
        
        CountDownLatch countDownLatch2 = new CountDownLatch(10);
        CountThread countThread2 = new CountThread("B", countDownLatch2, 10);
        ProgressBar progressBar2 = new ProgressBar();
        progressBar2.progressProperty().bind(countThread2.processProperty);
        
        Button btn = new Button();
        btn.setText("Start");
        btn.setOnAction(new EventHandler<ActionEvent>() {
            
            @Override
            public void handle(ActionEvent event) {
                System.out.println("Start");
                new Thread(countThread1).start();
                new Thread(countThread2).start();
            }
        });
        
        VBox vBox = new VBox();
        vBox.getChildren().addAll(btn, progressBar1, progressBar2);
        
        StackPane root = new StackPane();
        root.getChildren().add(vBox);
        
        Scene scene = new Scene(root, 300, 250);
        
        primaryStage.setTitle("java-buddy.blogspot.com");
        primaryStage.setScene(scene);
        primaryStage.show();
    }

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

class CountThread implements Runnable {

    int num_of_count = 5;
    CountDownLatch counter;
    String name;
    
    DoubleProperty processProperty;

    CountThread(String n, CountDownLatch c, int num) {
        name = n;
        counter = c;
        num_of_count = num;
        processProperty = new SimpleDoubleProperty(num_of_count);
    }

    @Override
    public void run() {

        for (int i = 0; i < num_of_count; i++) {
            try {
                Thread.sleep(1000);
            } catch (InterruptedException ex) {
                Logger.getLogger(CountThread.class.getName()).log(Level.SEVERE, null, ex);
            }
            
            processProperty.set((double)(counter.getCount())/(double)num_of_count);
            System.out.println(name + " : " + counter.getCount());
            counter.countDown();
            
        }
    }

}