NullPointerException is thrown on second method when using dependsOnMethods TestNG attribute with Selenium

Question

package testNG;

import java.util.concurrent.TimeUnit;

import org.openqa.selenium.*;
import org.openqa.selenium.WebDriver;
import org.testng.annotations.*;

public class TestNGUsingFacebook {

    WebDriver driver;

    @Test
    public void openBrowser() {

        try {
            System.setProperty("webdriver.chrome.driver", "C:\\Selenium\\chromedriver_win32\\chromedriver.exe");
            driver.manage().window().maximize();
            driver.manage().deleteAllCookies();
            driver.manage().timeouts().implicitlyWait(10, TimeUnit.SECONDS);
            driver.manage().timeouts().pageLoadTimeout(10, TimeUnit.SECONDS);
            driver.get("https://wwww.facebook.com");
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    @Test(dependsOnMethods = { "openBrowser" })
    public void loginToFacebook() {

        driver.findElement(By.id("email")).sendKeys("Neenad");
        driver.findElement(By.id("pass")).sendKeys("password");
        driver.findElement(By.id("loginbutton")).click();
    }

}

Whenever I try to run this sample code, I receive a null pointer exception as follows:

[RemoteTestNG] detected TestNG version 6.12.0
java.lang.NullPointerException
    at testNG.TestNGUsingFacebook.openBrowser(TestNGUsingFacebook.java:18)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.testng.internal.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:108)
    at org.testng.internal.Invoker.invokeMethod(Invoker.java:669)
    at org.testng.internal.Invoker.invokeTestMethod(Invoker.java:877)
    at org.testng.internal.Invoker.invokeTestMethods(Invoker.java:1201)
    at org.testng.internal.TestMethodWorker.invokeTestMethods(TestMethodWorker.java:125)
    at org.testng.internal.TestMethodWorker.run(TestMethodWorker.java:109)
    at org.testng.TestRunner.privateRun(TestRunner.java:776)
    at org.testng.TestRunner.run(TestRunner.java:634)
    at org.testng.SuiteRunner.runTest(SuiteRunner.java:425)
    at org.testng.SuiteRunner.runSequentially(SuiteRunner.java:420)
    at org.testng.SuiteRunner.privateRun(SuiteRunner.java:385)
    at org.testng.SuiteRunner.run(SuiteRunner.java:334)
    at org.testng.SuiteRunnerWorker.runSuite(SuiteRunnerWorker.java:52)
    at org.testng.SuiteRunnerWorker.run(SuiteRunnerWorker.java:86)
    at org.testng.TestNG.runSuitesSequentially(TestNG.java:1318)
    at org.testng.TestNG.runSuitesLocally(TestNG.java:1243)
    at org.testng.TestNG.runSuites(TestNG.java:1161)
    at org.testng.TestNG.run(TestNG.java:1129)
    at org.testng.remote.AbstractRemoteTestNG.run(AbstractRemoteTestNG.java:114)
    at org.testng.remote.RemoteTestNG.initAndRun(RemoteTestNG.java:251)
    at org.testng.remote.RemoteTestNG.main(RemoteTestNG.java:77)
PASSED: openBrowser
FAILED: loginToFacebook
java.lang.NullPointerException
    at testNG.TestNGUsingFacebook.loginToFacebook(TestNGUsingFacebook.java:32)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.testng.internal.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:108)
    at org.testng.internal.Invoker.invokeMethod(Invoker.java:669)
    at org.testng.internal.Invoker.invokeTestMethod(Invoker.java:877)
    at org.testng.internal.Invoker.invokeTestMethods(Invoker.java:1201)
    at org.testng.internal.TestMethodWorker.invokeTestMethods(TestMethodWorker.java:125)
    at org.testng.internal.TestMethodWorker.run(TestMethodWorker.java:109)
    at org.testng.TestRunner.privateRun(TestRunner.java:776)
    at org.testng.TestRunner.run(TestRunner.java:634)
    at org.testng.SuiteRunner.runTest(SuiteRunner.java:425)
    at org.testng.SuiteRunner.runSequentially(SuiteRunner.java:420)
    at org.testng.SuiteRunner.privateRun(SuiteRunner.java:385)
    at org.testng.SuiteRunner.run(SuiteRunner.java:334)
    at org.testng.SuiteRunnerWorker.runSuite(SuiteRunnerWorker.java:52)
    at org.testng.SuiteRunnerWorker.run(SuiteRunnerWorker.java:86)
    at org.testng.TestNG.runSuitesSequentially(TestNG.java:1318)
    at org.testng.TestNG.runSuitesLocally(TestNG.java:1243)
    at org.testng.TestNG.runSuites(TestNG.java:1161)
    at org.testng.TestNG.run(TestNG.java:1129)
    at org.testng.remote.AbstractRemoteTestNG.run(AbstractRemoteTestNG.java:114)
    at org.testng.remote.RemoteTestNG.initAndRun(RemoteTestNG.java:251)
    at org.testng.remote.RemoteTestNG.main(RemoteTestNG.java:77)


===============================================
    Default test
    Tests run: 2, Failures: 1, Skips: 0
===============================================

I have tried commenting the second function, but still Google Chrome does not open.

Answer 1

As it appears, though you are setting the property for the chrome driver through

System.setProperty("webdriver.chrome.driver", "C:\\Selenium\\chromedriver_win32\\chromedriver.exe");

You are not initializing the driver instance before using it like : driver.manage().window().maximize();

So please add the following line as follows:

System.setProperty("webdriver.chrome.driver", "C:\\Selenium\\chromedriver_win32\\chromedriver.exe"); // Setting the chrome driver property
driver = new ChromeDriver(); // Inializing the chrome driver

driver is the declared WebDriver instance in your above code.

Answer 2

There is one small mistake you made, You have forget to initiate the instance of webdriver. This is the reason why you found the null pointer exception.

As your project is in Java Based, So require to follow java code standards and formats as well.

Here is the correct code :

@Test
 public void openBrowser() {

try {
    System.setProperty("webdriver.chrome.driver", "C:\\Selenium\\chromedriver_win32\\chromedriver.exe");
    driver = new ChromeDriver(); // just add this line
    driver.manage().window().maximize();
    driver.manage().deleteAllCookies();
    driver.manage().timeouts().implicitlyWait(10, TimeUnit.SECONDS);
    driver.manage().timeouts().pageLoadTimeout(10, TimeUnit.SECONDS);
    driver.get("https://wwww.facebook.com");
} catch (Exception e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
}
}

---

Answer 3

You miss to instantiate the WebDriver. Add driver = new ChromeDriver(); in code after setProperty(), Rest is fine

try {
      System.setProperty("webdriver.chrome.driver", "C:\\Selenium\\chromedriver_win32\\chromedriver.exe");
      driver = new ChromeDriver();  
      driver.manage().window().maximize();
      driver.manage().deleteAllCookies();
      driver.manage().timeouts().implicitlyWait(10, TimeUnit.SECONDS);
      driver.manage().timeouts().pageLoadTimeout(10, TimeUnit.SECONDS);
      driver.get("https://wwww.facebook.com");
       } 
catch (Exception e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
       }