I am getting NPE when i try to validate a webElement using isDisplayed method. I am unable to access any webelement and action on it

Question

I have a base class as follows where I load the property file and initialize browser

package com.mystore.base;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.Properties;

//import org.apache.log4j.xml.DOMConfigurator;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.chrome.ChromeDriver;
import org.openqa.selenium.firefox.FirefoxDriver;
import org.openqa.selenium.ie.InternetExplorerDriver;
import org.openqa.selenium.support.PageFactory;
import org.testng.annotations.BeforeTest;

import io.github.bonigarcia.wdm.WebDriverManager;
import com.mystore.actiondriver.ActionDriver;


public class BaseClass1 {
    
    public static Properties prop;
    public static  WebDriver driver;
    //ActionDriver a = new ActionDriver();
    
    
    @BeforeTest
    public void loadConfig() {
        try {
            prop = new Properties();
            System.out.println("super constructor invoked");
            FileInputStream ip = new FileInputStream(
                    System.getProperty("user.dir") + "/Configuration/Config.properties");
            prop.load(ip);
            System.out.println("driver: "+ driver);

        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    
    public void launchApp() {
        
        String browserName = prop.getProperty("browser");
        
        if (browserName.equalsIgnoreCase("Chrome")) {
            WebDriverManager.chromedriver().setup();
            driver = new ChromeDriver();
            System.out.println("driver: "+ driver);
        } else if (browserName.equalsIgnoreCase("FireFox")) {
            WebDriverManager.firefoxdriver().setup();
            driver = new FirefoxDriver();
        } else if (browserName.equalsIgnoreCase("IE")) {
            WebDriverManager.iedriver().setup();
            driver = new InternetExplorerDriver();
        }
        
        ActionDriver.implicitWait(driver, 10);
        ActionDriver.pageLoadTimeOut(driver, 30);
        driver.get(prop.getProperty("url"));

    }
}

Index page class which inherits BaseClass and code below

package com.mystore.pageobjects;

import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.support.FindBy;
import org.openqa.selenium.support.PageFactory;

import com.mystore.actiondriver.ActionDriver;
import com.mystore.base.BaseClass;
import com.mystore.base.BaseClass1;

public class IndexPage1 extends BaseClass1{
    
    @FindBy(xpath = "//a[@class='login']")
    WebElement signInBtn;
    
    @FindBy(xpath = "//img[@class='logo img-responsive']")
    WebElement myStoreLogo;
    
    @FindBy(id="search_query_top")
    WebElement searchProductBox;
    
    @FindBy(name="submit_search")
    WebElement searchButton;
    
    public IndexPage1() {
        PageFactory.initElements(driver, this);
    }
    
    public LoginPage clickOnSignIn() {
        ActionDriver.click(driver,signInBtn);
        return new LoginPage();
    }
    
    public boolean validateLogo() throws Throwable{
        System.out.println("Inside Validate Logo");
        return myStoreLogo.isDisplayed();
        
        //return true;
        //return ActionDriver.isDisplayed(driver, myStoreLogo);
    }
    
    public String getMyStoreTitle() {
        String myStoreTitle = driver.getTitle();
        return myStoreTitle;
    }
    
    public SearchResultPage searchProduct(String productName) throws InterruptedException {
        Thread.sleep(10000);
        searchProductBox.sendKeys(productName);
        Thread.sleep(10000);
        System.out.println("I passed!");
        ActionDriver.type(searchProductBox, productName);
        ActionDriver.implicitWait(driver, 60);
        ActionDriver.click(driver, searchButton);
        return new SearchResultPage();
    }
}

IndexPageTest class with test - where I try to call verifyLogo() test which checks if webElement myStoreLogo is displayed and should return true but returns false and NPE .

package com.mystore.testcases;

import org.openqa.selenium.WebDriver;
import org.testng.Assert;
import org.testng.annotations.AfterMethod;
import org.testng.annotations.BeforeMethod;
import org.testng.annotations.Test;

import com.mystore.base.BaseClass;
import com.mystore.base.BaseClass1;
import com.mystore.pageobjects.IndexPage;
import com.mystore.pageobjects.IndexPage1;

public class IndexPageTest1 extends BaseClass1{

    IndexPage1 indexPage1 = new IndexPage1();
    
    @BeforeMethod
    public void setup() {
        launchApp(); 
    }
    
    //@AfterMethod
    public void tearDown() {
        driver.quit();
    }
    
    @Test()
    public void verifyLogo() throws Throwable{

        //indexPage1= new IndexPage();
        boolean result=indexPage1.validateLogo();
        System.out.println("The value of result is:"+ result);
        Assert.assertTrue(result);
        
    }
    
    @Test(enabled = false)
    public void verifySearchProduct() throws InterruptedException {
        indexPage1.searchProduct("t-shirt");
    }
    
    @Test(enabled=false)
    public void verifyTitle() {
        
        String actTitle=indexPage1.getMyStoreTitle();
        Assert.assertEquals(actTitle, "My Store");
        
    }
}

Gives results below

driver: ChromeDriver: chrome on MAC (fa4c8f6fb20e625d6d7e2b148850b17b)
Inside Validate Logo
FAILED: verifyLogo
java.lang.NullPointerException
    at org.openqa.selenium.support.pagefactory.DefaultElementLocator.findElement(DefaultElementLocator.java:69)
    at org.openqa.selenium.support.pagefactory.internal.LocatingElementHandler.invoke(LocatingElementHandler.java:38)
    at com.sun.proxy.$Proxy12.isDisplayed(Unknown Source)
    at com.mystore.pageobjects.IndexPage1.validateLogo(IndexPage1.java:47)
    at com.mystore.testcases.IndexPageTest1.verifyLogo(IndexPageTest1.java:40)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:567)
    at org.testng.internal.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:134)
    at org.testng.internal.TestInvoker.invokeMethod(TestInvoker.java:597)
    at org.testng.internal.TestInvoker.invokeTestMethod(TestInvoker.java:173)
    at org.testng.internal.MethodRunner.runInSequence(MethodRunner.java:46)
    at org.testng.internal.TestInvoker$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.base/java.util.ArrayList.forEach(ArrayList.java:1540)
    at org.testng.TestRunner.privateRun(TestRunner.java:766)
    at org.testng.TestRunner.run(TestRunner.java:587)
    at org.testng.SuiteRunner.runTest(SuiteRunner.java:384)
    at org.testng.SuiteRunner.runSequentially(SuiteRunner.java:378)
    at org.testng.SuiteRunner.privateRun(SuiteRunner.java:337)
    at org.testng.SuiteRunner.run(SuiteRunner.java:286)
    at org.testng.SuiteRunnerWorker.runSuite(SuiteRunnerWorker.java:53)
    at org.testng.SuiteRunnerWorker.run(SuiteRunnerWorker.java:96)
    at org.testng.TestNG.runSuitesSequentially(TestNG.java:1187)
    at org.testng.TestNG.runSuitesLocally(TestNG.java:1109)
    at org.testng.TestNG.runSuites(TestNG.java:1039)
    at org.testng.TestNG.run(TestNG.java:1007)
    at org.testng.remote.AbstractRemoteTestNG.run(AbstractRemoteTestNG.java:115)
    at org.testng.remote.RemoteTestNG.initAndRun(RemoteTestNG.java:251)
    at org.testng.remote.RemoteTestNG.main(RemoteTestNG.java:77)


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

Please help, I'm not sure why the webelement is not identified. I tried with other web elements and they also get the same NPE.

driver is probably null. (LaunchApp() method should be called earlier? In @beforetest?) Track down the initialization and pass the reference into constructors when necessary. Also might want to re-consider declaring the webdriver as static. — pcalkins, Oct 26 '22 at 20:34
I have the webdriver static in BaseClass and also the LaunchApp() is called in @BeforeMethod in IndexPageTest1 class — Anu, Oct 27 '22 at 22:11
When i use @FindBy method for identifiying objects in POM and use PageFactory.initElements(driver, this) to initialize the elements, i am getting this error. I am new to frameworks and am trying to build one, and clueless, if there is anything else, that needs to be done for PageFactory(any files needed). PageFactory package is imported — Anu, Oct 27 '22 at 22:16
I never use POM or TestNG, so I'm not sure I can help much. Maybe see this thread: https://stackoverflow.com/questions/50811759/what-is-the-difference-between-beforetest-and-beforemethod-in-testng Right now your IndexPage1 constructor is calling PageFactory.initElements(driver, this);... but driver has not been initialized or passed in as a reference. Your "launchApp()" method initializes the driver but that's in a @BeforeMethod annotation, which I think gets called before each method? That doesn't seem right. — pcalkins, Oct 27 '22 at 22:34

score 1 · Answer 1 · answered Oct 28 '22 at 06:20

The problem lies in your test code.

The WebDriver object that is part of your base class BaseClass1 is getting initialised only when the method launchApp() is invoked.
But the constructor of your page class IndexPage1 already tries to access the WebDriver object (which at the time of instantiation of IndexPage1 is null)
So you end up invoking PageFactory.initElements(driver, this); with a null value for driver

Solution.

Please remove the logic of managing your webdriver instances via your base class and segregate it to a separate utility method which when called can give you a WebDriver object. Alternatively you can also make use of a library such as Autospawn that I created which uses an annotation way of managing webdriver instances. - The documentation should explain how to use this library. Note that if you use this library, you would need to create all your page classes within your @Test method (because that's the only place wherein a valid WebDriver instance would be available in the current Thread's context)
Refactor your IndexPage1 class's constructor so that it accepts a WebDriver instance as a parameter from outside.

I am getting NPE when i try to validate a webElement using isDisplayed method. I am unable to access any webelement and action on it

1 Answers1