firefox driver download- null pointer exception_using java selenium webdriver with TestNG

Question

While executing the code below , null pointer exception is occuring, as driver of class Pom_MainHerokuapp is always null

testcases:-

package testcases;

import java.util.concurrent.TimeUnit;

import org.openqa.selenium.WebDriver;

import org.openqa.selenium.firefox.FirefoxDriver;

import org.testng.annotations.Test;

import poms.Pom_MainHerokuapp;

import testbase.TestBase;

public class MainHerokuapp extends TestBase {

    Pom_MainHerokuapp mainHerokuappObject;

    public MainHerokuapp() {

        mainHerokuappObject = new Pom_MainHerokuapp(driver);

    }

    @Test(priority = 0)

    public void TestMainpagetitle() {

        mainHerokuappObject.VerifyTitles();

    }

    @Test(priority = 1)

    public void TestABTestingText() {

        mainHerokuappObject.VerifyTextOfABTesting();

    }

}

TestBase class:-

package testbase;

import java.util.concurrent.TimeUnit;

import org.openqa.selenium.WebDriver;

import org.openqa.selenium.firefox.FirefoxDriver;

import org.testng.annotations.BeforeTest;

public class TestBase {

    public WebDriver driver;

    @BeforeTest

    public void setup() {

        driver = new FirefoxDriver();

        driver.get("https://the-internet.herokuapp.com/");

        driver.manage().window().maximize();

        driver.manage().timeouts().implicitlyWait(30, TimeUnit.SECONDS);

    }

}

Also:

package poms;

import org.openqa.selenium.WebDriver;

import org.openqa.selenium.WebElement;

import org.openqa.selenium.support.FindBy;

import org.openqa.selenium.support.PageFactory;

import org.testng.Assert;

public class Pom_MainHerokuapp {

    public WebDriver driver;

    String text;

    String StringMaintext;

    String Stringsubtitle;

    @FindBy(xpath = "//html//body//div[2]//div//h1")

    WebElement Maintitle;

    @FindBy(xpath = "//html//body//div[2]//div//h2")

    WebElement Subtitle;

    @FindBy(linkText = "A/B Testing")

    WebElement ABTesting;

    @FindBy(xpath = "//html//body//div[2]//div//div//h3")

    WebElement ABTestingText;

    create constructor of this class

    public Pom_MainHerokuapp(WebDriver driver) {

        this.driver = driver;

        PageFactory.initElements(driver, this); // Initialization all webelements  

    }

    public void VerifyTitles() {

        StringMaintext = Maintitle.getText();

        Stringsubtitle = Subtitle.getText();

        System.out.println(StringMaintext);

        System.out.println(Stringsubtitle);

        Assert.assertEquals(StringMaintext, "Welcome to the Internet");

        Assert.assertEquals(Stringsubtitle, "Available Examples");

    }

    public void VerifyTextOfABTesting() {

        ABTesting.click();

        text = ABTestingText.getText();

        System.out.println(text);

        Assert.assertEquals(text, "A/B Test Variation 1");

    }

}

the error is :-

FAILED: TestMainpagetitle java.lang.NullPointerException at org.openqa.selenium.support.pagefactory.DefaultElementLocator.findElement(DefaultElementLocator.java:69)

Answer 1

This isn't hard to explain. The default constructor of your test class MainHerokuapp will be called as soon as it is run, i.e. when the driver is still null - before your @BeforeTest method, where the driver gets set.

 

MainHerokuapp and TestBase seem to be mixed-up rather than having a clear separation, so you'd be better off merging them back into one.

 

Another way is to restore control to the child class by dropping the constructor, moving the @BeforeTest there, and calling up to the parent. This definitely works:

 public class MainHerokuapp extends TestBase {

    Pom_MainHerokuapp mainHerokuappObject;

    @BeforeTest

    public void setup() {

        super.setup();

        mainHerokuappObject = new Pom_MainHerokuapp(driver);

    }

    @Test(priority = 0)

    public void TestMainpagetitle() {

        mainHerokuappObject.VerifyTitles();

    }

    @Test(priority = 1)

    public void TestABTestingText() {

        mainHerokuappObject.VerifyTextOfABTesting();

    }

}

public class TestBase {

    public WebDriver driver;

    // @BeforeTest

    public void setup() {

        driver = new FirefoxDriver();

        driver.get("https://google.com/");

        driver.manage().window().maximize();

        driver.manage().timeouts().implicitlyWait(30, TimeUnit.SECONDS);

    }

}