"public ThreadLocal<WebDriver> webdriver = new ThreadLocal<WebDriver><WebDriver>();" yöntemini kullanırken Dinleyici sınıfım için WebDriver nasıl edinilir

Dinleyicimin WEB sürücüsü için NullPointerException almaya devam ediyorum. temel sınıfta webdriver'ımda ThreadLocal kullandığım için mi? eğer öyleyse, dinleyicimin onTestSuccess yöntemi için test durumunun sürücüsünü nasıl alabilirim?

Bu benim Dinleyici Sınıfım.:

@Override
    public void onTestSuccess(ITestResult result) {
        extentTest.get().log(Status.PASS,"Test Passed");
        WebDriver driver = null;
        Object testObject = result.getInstance();
        Class clazz = result.getTestClass().getRealClass();
        try {
            driver = (WebDriver)clazz.getField("webdriver").get(testObject);
        } catch (Exception e) {
        }
        try {
            extentTest.get().addScreenCaptureFromPath(getScreenShotPath(result.getMethod().getMethodName(), driver), result.getMethod().getMethodName());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

Temel Sınıf:

public ThreadLocal<WebDriver> webdriver = new ThreadLocal<WebDriver>();


@BeforeClass
public void setup() {
    Reporter.log("@@@@@ Setup @@@@@",true);
    ExtentReports extent = ExtentReport.extentReportGenerator();
}


@BeforeMethod
public void startBrowser() {
    WebDriverFactory webDriverFactory = new WebDriverFactory();
    webDriverFactory.setDriver();
    webdriver.set(webDriverFactory.getDriver());
    webdriver.get().get(baseURL);

TestCase Sınıfı:

@Test(dataProvider = "jsonData", dataProviderClass = TestData.class)
public void  testAggregator(String jSon) throws ParseException {
    extent.createTest("Test The Welcome Page");
    welcomePageImpl = new WelcomePageImpl(webdriver.get());
    welcomePageImpl.getAggregatorRequest(webdriver.get(),jSon);
}

İstisna:

java.lang.NullPointerException
    at main.java.com.shoppingCart.testCases.BaseClass.getScreenShotPath(BaseClass.java:71)
    at main.java.com.shoppingCart.utilities.Listeners.onTestSuccess(Listeners.java:37)
    at org.testng.internal.TestListenerHelper.runTestListeners(TestListenerHelper.java:70)
    at org.testng.internal.TestInvoker.runTestResultListener(TestInvoker.java:219)
    at org.testng.internal.TestInvoker.invokeMethod(TestInvoker.java:651)
    at org.testng.internal.TestInvoker.invokeTestMethod(TestInvoker.java:173)
    at org.testng.internal.MethodRunner.runInSequence(MethodRunner.java:46)
    at org.testng.internal.TestInvoker$MethodInvocationAgent.invoke(TestInvoker.java:816)
    at org.testng.internal.TestInvoker.invokeTestMethods(TestInvoker.java:146)
    at org.testng.internal.TestMethodWorker.invokeTestMethods(TestMethodWorker.java:146)
    at org.testng.internal.TestMethodWorker.run(TestMethodWorker.java:128)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at java.lang.Thread.run(Thread.java:748)