Null Pointer Exception while running code using TestNG

Question

I am trying to automate a Login and Logout Scenario in TestNG and passing the browser as parameter from XML on the basis of which chromedriver() instance will be created and the code will run.I have two classes TestRunner and Login where login method gets data (username and password) TestRunner and data is fetched from excel.Exception e is getting null value as I found out while debugging. Any way to fix it?

FAILED: Registration_data("ashwin@gmail.com", "ashwin123")
java.lang.NullPointerException
at com.DataDriven.Login.login(Login.java:68)
at com.DataDriven.TestRunner.Registration_data(TestRunner.java:28)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at   sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at   sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:483)
at   org.testng.internal.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:84)
at org.testng.internal.Invoker.invokeMethod(Invoker.java:714)
at org.testng.internal.Invoker.invokeTestMethod(Invoker.java:901)
at org.testng.internal.Invoker.invokeTestMethods(Invoker.java:1231)
at     org.testng.internal.TestMethodWorker.invokeTestMethods(TestMethodWorker.java:12)
at org.testng.internal.TestMethodWorker.run(TestMethodWorker.java:111)
at org.testng.TestRunner.privateRun(TestRunner.java:767)
at org.testng.TestRunner.run(TestRunner.java:617)
at org.testng.SuiteRunner.runTest(SuiteRunner.java:334)
at org.testng.SuiteRunner.runSequentially(SuiteRunner.java:329)
at org.testng.SuiteRunner.privateRun(SuiteRunner.java:291)
at org.testng.SuiteRunner.run(SuiteRunner.java:240)
at org.testng.SuiteRunnerWorker.runSuite(SuiteRunnerWorker.java:52)
at org.testng.SuiteRunnerWorker.run(SuiteRunnerWorker.java:86)
at org.testng.TestNG.runSuitesSequentially(TestNG.java:1224)
at org.testng.TestNG.runSuitesLocally(TestNG.java:1149)
at org.testng.TestNG.run(TestNG.java:1057)
at org.testng.remote.RemoteTestNG.run(RemoteTestNG.java:111)
at org.testng.remote.RemoteTestNG.initAndRun(RemoteTestNG.java:204)

    package com.DataDriven;
    import java.util.concurrent.TimeUnit;
    import org.openqa.selenium.By;
    import org.openqa.selenium.WebDriver;
    import org.openqa.selenium.firefox.FirefoxDriver;
    public class TestRunner {

    @Test(dataProvider = "Authentication")
    public static void Registration_data(String sUserName, String sPassword)
        throws Exception {

    Login lp = new Login();
    lp.login(sUserName, sPassword);
    }

    @DataProvider
    public Object[][] Authentication() throws Exception {

    Object[][] testObjArray = ReadData.getTableArray(
            "F:\\Automation\\DataDrivenPractice\\DataFiles\\DataFile.xlsx",
            "Sheet1");

    return (testObjArray);  }  }

    package com.DataDriven;

    import java.io.File;

    import org.apache.commons.io.FileUtils;
    import org.openqa.selenium.By;
    import org.openqa.selenium.OutputType;
    import org.openqa.selenium.TakesScreenshot;
    import org.openqa.selenium.WebDriver;
    import org.openqa.selenium.chrome.ChromeDriver;

    public class Login {
     WebDriver driver = null;

     @Parameters("browser")
     @BeforeClass
    // Passing Browser parameter from TestNG xml
    public void beforeTest(String browser) {

    // If the browser is Firefox, then do this

    if (browser.equalsIgnoreCase("firefox")) {

        driver = new FirefoxDriver();

        // If browser is IE, then do this

      } else if (browser.equalsIgnoreCase("chrome")) {

        // Here I am setting up the path for my IEDriver

        driver = new ChromeDriver(); } }

     public void login(String username, String password) {
        try {
        driver.get("https://www.facebook.com/");

        driver.findElement(By.id("email")).sendKeys(username);
        driver.findElement(By.id("pass")).sendKeys(password);
        driver.findElement(By.id("loginbutton")).click();
        driver.findElement(By.linkText("Log Out")).click();
         }

       catch (Exception e) {
        File srcfile = ((TakesScreenshot) driver)
                .getScreenshotAs(OutputType.FILE);

        try {
            FileUtils.copyFile(srcfile, new File(
                    "F:\\Automation\\Screenshots\\Login.jpg"));
        } catch (Exception e1) {
            e1.printStackTrace();
        }   }  }}

        <?xml version="1.0" encoding="UTF-8"?>
        <!DOCTYPE suite SYSTEM "http://testng.org/testng-1.0.dtd">
        <suite name="Suite" parallel="none">
        <test name="FirefoxTest">
         <parameter name="browser" value="chrome" />
         <classes>
         <class name="com.DataDriven.TestRunner" />
         <class name="com.DataDriven.Login" /> 
         </classes>
         </test>
         </suite>

possible duplicate of [What is a Null Pointer Exception, and how do I fix it?](http://stackoverflow.com/questions/218384/what-is-a-null-pointer-exception-and-how-do-i-fix-it) — Jens, Mar 15 '15 at 19:25
I would recommend stepping through this with a debugger, to make sure that `driver` is being set to what you think it's being set to, and to find out exactly which value is unexpectedly null. — Dawood ibn Kareem, Mar 15 '15 at 19:27
@DavidWallace Exception e is getting null value. Any idea how to fix it? — Ashwiinn Karaangutkar, Mar 15 '15 at 19:30
@DavidWallace Yes, I did debugging and it says Exception e is getting value as null. — Ashwiinn Karaangutkar, Mar 15 '15 at 19:36
So, before the exception is thrown, which value is unexpectedly null? — Dawood ibn Kareem, Mar 15 '15 at 19:40

Nguyen Vu Hoang · Answer 1 · 2015-03-17T05:49:04.803

There are many issues in your scripts

1 - Your classes init separately. The driver from @BeforeClass doesnot inherite into your @Test

2 - When you do

Login lp = new Login();

you have

WebDriver driver = null;
@BeforeClass is not invoked, no driver init, your driver is still null

Then

lp.login(sUserName, sPassword);

NullPointException throws because driver in following line of code is null

driver.get("https://www.facebook.com/");

Suggest action

You need to get driver goes through all your classes

TestBase.class

Put your @BeforeClass here

LoginPage.class, be sure you allow to cast driver into it

public LoginPage(WebDriver driver) {
    // your code here
}    

// Put login(sUserName, sPassword) method here

TestRunner.class

inherite/extends from TestBase.class
LoginPage lp = new LoginPage(driver);
lp.login(sUserName, sPassword);

Fenio · Answer 2 · 2015-03-15T20:28:15.160

0

Your problem is - your method beforeTest doesn't invoke. Your driver doesn't point to any type of object.

TestNG search through all your classes only for @Test annotation. How it's supposed to know that @BeforeClass annotation lies in specific class you've created?

To run @BeforeClass annotation, you either have to set extends for Login class (it won't be effective for multiple scripts) or run beforeTest method manually. Or set it to running class containing @Test annotation.

Correct me if i'm wrong. Hope it helps!

EDIT:

Move your method and WebDriver variable to Test Runner Class

 WebDriver driver = null;

 @Parameters("browser")
 @BeforeClass
// Passing Browser parameter from TestNG xml
public void beforeTest(String browser) {

// If the browser is Firefox, then do this

if (browser.equalsIgnoreCase("firefox")) {

    driver = new FirefoxDriver();

    // If browser is IE, then do this

  } else if (browser.equalsIgnoreCase("chrome")) {

    // Here I am setting up the path for my IEDriver

    driver = new ChromeDriver(); } }

TestRunner class should contain both, @Test and @BeforeClass. As TestNG reads Annotations from classes containing @Test annotation.

edited Mar 15 '15 at 20:28

answered Mar 15 '15 at 19:53

Fenio

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You're correct that `beforeTest()` isn't being called, but your reasoning isn't quite right. TestNG *does* searches classes for annotations, but only for `@Test`, all other TestNG annotations are inspected after the classes have been found. Your comment about "setting" `extends` doesn't make any sense; there's no need to extend anything. – dimo414 Mar 15 '15 at 20:03
I would still work, tho! I used to create "Settings" class as a major settings for all `@Tests` and every `@Test` class extended `Settings` class. With this kind of solution, TestNG invokes `@BeforeClass` and `@Test`. It's kind of specific solution. I corrected my answer according to your comment. Thanks! – Fenio Mar 15 '15 at 20:09
Are you trying to suggest `TestRunner extends Login`? – dimo414 Mar 15 '15 at 20:14
In this particullary scenario it won't be a good solution, but this is what i meant, answering this question. E.g.: `Login extends BasicSettings` or `TestRunner extends Login` – Fenio Mar 15 '15 at 20:16
I marked my login method as @Test and ran my class now my beforeTest method is getting invoked but now I am getting error as : org.testng.TestNGException: Method login requires 2 parameters but 0 were supplied in the Test annotation. ... Removed 23 stack frames Cant understand why values are not getting supplied, any idea why? – Ashwiinn Karaangutkar Mar 15 '15 at 20:17

Null Pointer Exception while running code using TestNG

2 Answers2