无法在 Java 中访问子类中的父类对象属性

Question

My question is pretty straightforward I have parent class and I have created a new driver object of webdriver class there In my subclass I am able to access the driver object but its value is null I am not able to access the object properties My parent Class is

public class BaseTest {

    public static  WebDriver driver;
    @BeforeTest
    @Parameters("browser")
    public void  VerifyPageTitle(String browser)
    {
        if(browser.equalsIgnoreCase("chrome")){
            System.setProperty("webdriver.chrome.driver","C://chromedriver_win32(1)//chromedriver_win32//chromedriver.exe");
             driver = new ChromeDriver();
        }
        if(browser.equalsIgnoreCase("IE")){
            System.setProperty("webdriver.ie.driver","C://IEDriverServer_x64_3.3.0//IEDriverServer.exe");
            driver = new InternetExplorerDriver();
        }
        driver.manage().window().maximize();
    }
}

in my sub-class code

public class SignPageTest extends BaseTest{

    SignPage obj ;
    Boolean stu;
    @Test
    public void navigateToSignPage(){
    obj = new SignPage(driver);
    stu = obj.navigateToSignIn();
    }
    @Test(priority=2)
    public void getHandles(){
        stu = obj.handlingWindows();
    }

}

I am getting null-pointer as my driver is not initialized So please tell me the way to simply access the objects properties of super-class

the moment I make my driver as static I am able to access its properties in all other classes but I don't want it to be static

Answer 1

The problem lies in your test code.

You are initialising a WebDriver instance via an @BeforeTest annotated method. TestNG invokes a @BeforeTest method only ONCE per <test> tag. So the below combination (which am guessing is what you have) will cause NullPointerException in the @Test methods of the second class.

• You have SignPageTest extend BaseTest and lets say you have another class called SomeFlowTest which also extends BaseTest
• You have created a <test> that includes both SignPageTest and SomeFlowTest .

This would cause the @BeforeTest to be executed only once for either SignPageTest (or) SomeFlowTest (depending upon the order in which they occur in your <test> tag), because both these classes extend from the same base class. So once TestNG executes VerifyPageTitle() via SignPageTest it will not execute the same method via SomeFlowTest and so the WebDriver instance for SomeFlowTest is null.

To fix this problem change @BeforeTest to either @BeforeClass (gets executed once per test class) or @BeforeMethod (gets executed for every @Test method).