how to get WebDriver for my Listener class when using "public ThreadLocal<WebDriver> webdriver = new ThreadLocal<WebDriver>();" method

Question

I keep getting NullPointerException for my Listener's WebDriver. is this because I used ThreadLocal on my WebDriver in base class? if so how do I get the test case's driver for my listener's onTestSuccess method?

This is my Listener Class:

@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();
        }
    }

BaseClass:

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 Class:

@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);
}

Exception:

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)

Answer 1

The problem is in your test code.

onSuccess is NOT guaranteed by TestNG to run in the same thread as your test method.

To fix this, please refactor your listener to use beforeInvocation and afterInvocation via the TestNG listener interface org.testng.IInvokedMethodListener because that is guaranteed to run on the same thread (as far as I can remember).