使用页面工厂运行测试时出现NullPointerException

Question

I get an exception when I run my test. I am using selenium with page factory. When I run following code ,it will open up the website and fail with exception below. it doesn't perform the HomePage.ClickbtnCookieWarning() in my test case.

Can someone please help me to understand why my code isn't working?

FAILED CONFIGURATION: @BeforeTest SetUp 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.$Proxy5.click(Unknown Source) at pageObjects.HomePage.ClickLoginLink(HomePage.java:57) at myaccountsuite.TC1DefaultDeliveryAddDisplay.SetUp(TC1DefaultDeliveryAddDisplay.java:29)

Home Page page object

public class HomePage {

    WebDriver driver;

    public HomePage (WebDriver driver)
    {
        this.driver=driver;         
    }

    @FindBy(id="ctl00_header_hdrCookieWarning_btnHideCookieWarning")
    WebElement btnCookieWarning;

    @FindBy(xpath=".//*@id='ctl00_masterContainerTop_Block_637_LoginView1_ulAnonymous']/li[2]/a")
    WebElement LoginLink;

    public void ClickbtnCookieWarning()
    {
        btnCookieWarning.click();
    }

    public void ClickLoginLink()
    {
        LoginLink.click();
    }
}

Login Page Object

public class login {

    WebDriver driver;

    public login(WebDriver driver)
    {
        this.driver = driver; 
    } 

    @FindBy(id="ctl00_ContentPlaceHolderMain_container_container_Block_166_lgn1_UserName")
    WebElement UserName;

    @FindBy(id="ctl00_ContentPlaceHolderMain_container_container_Block_166_lgn1_Password")
    WebElement Password;

    @FindBy(id="ctl00_ContentPlaceHolderMain_container_container_Block_166_lgn1_LoginButton")
    WebElement btn_LogIn;

    @FindBy(id="ctl00_ContentPlaceHolderMain_container_container_Block_166_lgn1_txtAccount")
    WebElement Account;

    @FindBy(id="ctl00_ContentPlaceHolderMain_container_container_Block_166_lgn1_btnHomeBranch_3")
    WebElement btn_Continue;

    public void userLogin(String uname, String pass, String acc) 
    {
        UserName.sendKeys(uname);
        Password.sendKeys(pass);
        btn_LogIn.click();
        driver.manage().timeouts().implicitlyWait(60, TimeUnit.SECONDS);
        Account.sendKeys(acc);
        btn_LogIn.click();
        btn_Continue.click();
    }     
}

My Test

public class TC1DefaultDeliveryAddDisplay {
    public WebDriver driver;

    @BeforeTest(alwaysRun = true)
    public void SetUp() {

        HomePage HomePage = PageFactory.initElements(driver, HomePage.class);
        login loginpage = PageFactory.initElements(driver, login.class);

        driver = new FirefoxDriver();
        driver.get("http://URL/");
        HomePage.ClickbtnCookieWarning();
        HomePage.ClickLoginLink();
        loginpage.userLogin("aa@yahoo.com", "125", "Test");

    }

Answer 1

You're getting NullPointerException because you're using WebDriver instance before initialising.

You need to Initialize WebDriver before using this instance as :-

driver = new FirefoxDriver();
HomePage HomePage = PageFactory.initElements(driver, HomePage.class); 
Login loginpage =PageFactory.initElements(driver, login.class);

If you want to use WebDriver as singleton which returns single instance for all your test methods you can follow this answer which is exactly you want .

Answer 2

The problem is in each class you are creating new instance of driver. You just need to create one driver instance in you base class where you do your browser setup. Please refer Page Object Model. Once the Driver instance is created you need to use the same in all your classes. Or else it will throw NullPointerException because driver will not have any reference.