TestNG WebDriver Session Cleanup Code

TestBase.js

/**
 * Simple TestNG test which demonstrates being instantiated via a DataProvider in order to supply multiple browser combinations.
 *
 * @authors Neil Manvar, Dylan Lacey
 */
public class TestBase  {

// SNIP

    /**
     * ThreadLocal variable which contains the Shutdown Hook instance for this Thread's WebDriver.
     *
     * Registered just before Browser creation, de-registered after 'quit' is called.
     */
    private ThreadLocal<Thread> shutdownHook = new ThreadLocal<>();

    /**
     * Creates the shutdownHook, or returns an existing copy
     */
    private Thread getShutdownHook() {
        if (shutdownHook.get() == null) {
            shutdownHook.set( new Thread(() -> {
                try {
                    if (webDriver.get() != null) webDriver.get().quit();
                } catch (org.openqa.selenium.NoSuchSessionException ignored) { } // Don't care if session already closed
            }));
        }
        return shutdownHook.get();
    }

    /**
     * Registers the shutdownHook with the runtime.
     *
     * Ignoring exceptions on registration; They mean the VM is already shutting down and it's too late.
     */
    private void registerShutdownHook() {
        // Register a hook to always close this session.  Only works/needed once session is created.
        try {
            Runtime.getRuntime().addShutdownHook(getShutdownHook());
        } catch (IllegalStateException ignored) {} // Thrown if a hook is added while shutting down; We don't care
    }

    /**
     * De-registers the shutdownHook. This allows the GC to remove the thread and avoids double-quitting.
     *
     * Silently swallows exceptions if the VM is already shutting down; it's too late.
     */
    private void deregisterShutdownHook() {
        if (shutdownHook.get() != null) {
            try {
                Runtime.getRuntime().removeShutdownHook(getShutdownHook());
            } catch (IllegalStateException ignored) { } // VM already shutting down; Irrelevant
        }
    }

 // SNIP 

    /**
     * Constructs a new {@link RemoteWebDriver} instance which is configured to use the capabilities defined by the browser,
     * version and os parameters, and which is configured to run against ondemand.saucelabs.com, using
     * the username and access key populated by the {@link #authentication} instance.
     *
     * @param browser Represents the browser to be used as part of the test run.
     * @param version Represents the version of the browser to be used as part of the test run.
     * @param os Represents the operating system to be used as part of the test run.
     * @param methodName Represents the name of the test case that will be used to identify the test on Sauce.
     * @return
     * @throws MalformedURLException if an error occurs parsing the url
     */
    protected void createDriver(String browser, String version, String os, String methodName)

// SNIP

        webDriver.set(new RemoteWebDriver(
                new URL("https://" + username + ":" + accesskey + "@ondemand.saucelabs.com/wd/hub"),
                capabilities));

        registerShutdownHook();

        // set current sessionId
        String id = ((RemoteWebDriver) getWebDriver()).getSessionId().toString();
        sessionId.set(id);
    }

    /**
     * Method that gets invoked after test.
     * Dumps browser log and
     * Closes the browser
     */
    @AfterMethod
    public void tearDown(ITestResult result) throws Exception {
        ((JavascriptExecutor) webDriver.get()).executeScript("sauce:job-result=" + (result.isSuccess() ? "passed" : "failed"));
        webDriver.get().quit();
        deregisterShutdownHook();
    }

//SNIP 
}