A JavaFX program to find out the mouse refresh rate v3

Question

(This post is the continuation of A JavaFX program to find out the mouse refresh rate v2.)

After taking @J_H's suggestions into account, I ended up here:

com.github.coderodde.javafx.mouseupdaterate.MouseRefreshRateFinder.java:

package com.github.coderodde.javafx.mouseupdaterate;
import java.text.DecimalFormat;
import java.text.DecimalFormatSymbols;
import javafx.application.Application;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.canvas.Canvas;
import javafx.scene.input.MouseEvent;
import javafx.stage.Stage;
public final class MouseRefreshRateFinder extends Application {
 /**
 * Screen width in pixels.
 */
 private static final int SCREEN_WIDTH = 800;
 
 /**
 * Screen height in pixels.
 */
 private static final int SCREEN_HEIGHT = 600;
 
 /**
 * Used in {@code DURATION_DECIMAL_FORMAT} and 
 * {@code FREQUENCY_DECIMAL_FORMAT}.
 */
 private static DecimalFormatSymbols DECIMAL_FORMAT_SYMBOLS =
 DecimalFormatSymbols.getInstance();
 
 static {
 DECIMAL_FORMAT_SYMBOLS.setDecimalSeparator('.');
 }
 
 /**
 * The decimal formatter for duration.
 */
 private static final DecimalFormat DURATION_DECIMAL_FORMAT =
 new DecimalFormat("0.00", DECIMAL_FORMAT_SYMBOLS);
 /**
 * The decimal formatter for frequencies.
 */
 private static final DecimalFormat FREQUENCY_DECIMAL_FORMAT =
 new DecimalFormat("0.0", DECIMAL_FORMAT_SYMBOLS);
 
 static {
 // Garbage-collect since unused from now on:
 DECIMAL_FORMAT_SYMBOLS = null;
 }
 
 public static void main(String[] args) {
 launch(args);
 }
 @Override
 public void start(Stage stage) {
 Group root = new Group();
 MyMouseListener listener = new MyMouseListener();
 Canvas canvas = new Canvas(SCREEN_WIDTH, SCREEN_HEIGHT);
 
 // Add the event listeners:
 canvas.addEventHandler(MouseEvent.MOUSE_PRESSED, 
 listener::handlePressed);
 
 canvas.addEventHandler(MouseEvent.MOUSE_DRAGGED, 
 listener::handleDragged);
 
 canvas.addEventHandler(MouseEvent.MOUSE_RELEASED, 
 listener::handleReleased);
 root.getChildren().add(canvas);
 stage.setScene(new Scene(root));
 stage.show();
 }
 private static final class MyMouseListener {
 private long dragStartNanoseconds;
 private int frameCounter;
 public void handlePressed(MouseEvent t) {
 dragStartNanoseconds = System.nanoTime();
 frameCounter = 0;
 }
 public void handleDragged(MouseEvent t) {
 frameCounter++;
 }
 public void handleReleased(MouseEvent t) {
 double durationInNanoseconds = 
 System.nanoTime() - dragStartNanoseconds;
 
 double durationInSeconds = durationInNanoseconds / 1e9;
 
 String durationInSecondsString = 
 DURATION_DECIMAL_FORMAT.format(durationInSeconds);
 
 String frequencyString = 
 FREQUENCY_DECIMAL_FORMAT
 .format(frameCounter / durationInSeconds);
 
 System.out.printf(
 "%d frames in %s s, refresh rate of %s Hz.%n",
 frameCounter, 
 durationInSecondsString,
 frequencyString);
 }
 }
}

Critique request

As always, I would like to hear about all possible improvements to my program.

• Reinderien: What is the machine locale? This is kind of.. Not in the spirit of JH's suggestion, necessarily. What is the purpose of formatting decimals in a different style from the default locale?
• Reinderien: Is your machine locale fi_FI? What is the value of Locale.getDefault();?
• coderodde: @Reinderien I will check my default locale tomorrow. Now tired.