Java program is not terminating when using Selenium Webdriver

Question

As described in the question, when i initialize an instance of selenium web driver, my java program does not close after the main method has finished running. I am using the sample code from the official Selenium documentation:

public static void main(String[] args) {
    System.setProperty("webdriver.gecko.driver", pathToWebdriver);
    WebDriver driver = new FirefoxDriver();
    WebDriverWait wait = new WebDriverWait(driver, Duration.ofSeconds(10));
    try {
        driver.get("https://google.com/ncr");
        driver.findElement(By.name("q")).sendKeys("cheese" + Keys.ENTER);
        WebElement firstResult = wait.until(presenceOfElementLocated(By.cssSelector("h3>div")));
        System.out.println(firstResult.getAttribute("textContent"));
    } finally {
        driver.quit();
    }
    System.out.println(Thread.getAllStackTraces().keySet());
}

Output:

[Thread[ForkJoinPool.commonPool-worker-3,5,main], Thread[Monitor Ctrl-Break,5,main], Thread[AsyncHttpClient-3-1,5,main], Thread[Signal Dispatcher,9,system], Thread[Common-Cleaner,8,InnocuousThreadGroup], Thread[process reaper,10,system], Thread[Reference Handler,10,system], Thread[AsyncHttpClient-timer-1-1,5,main], Thread[Attach Listener,9,system], Thread[AsyncHttpClient-timer-4-1,5,main], Thread[Finalizer,8,system], Thread[main,5,main]]

PS: Its the same if im using chrome webdriver or driver.close()

Edit: This problem seems to be selenium-4.0.0-alpha only