Can @findby annotation be used in an interface with Selenium

Question

Lets see below code:

public interface HomePageObjects {

    @FindBy(xpath = "//*[@class='_2zrpKA']")
    WebElement UsernameField ;

    @FindBy(xpath = "//*[@class='_2zrpKA _3v41xv']")
    WebElement PswdField ;

}

public class HomePageTests implements HomePageObjects {

    WebDriver Driver;

    @BeforeClass
    public void initpage() {
        Driver = LaunchBrowser.Driver;
        PageFactory.initElements(Driver, this); 
        System.out.println(UsernameField + " " + Driver);
    }

}

This code compiles fine, but it is not able to initialize webelements, does any one has an explanation?

Answer 1

The source code for the PageFactory class , check the initElements method.

public static void initElements(FieldDecorator decorator, Object page) {
    Class<?> proxyIn = page.getClass();
    while (proxyIn != Object.class) {
      proxyFields(decorator, page, proxyIn);
      proxyIn = proxyIn.getSuperclass();
    }
  }

The proxyIn.getSuperclass() returns the superclass of the pageobject ignoring the interface. So in your case it goes from HomePageTests.class to Object.class . Thus the webelements in the interface will remain uninitialized. You can look at using an abstract class instead which is a better idea for storing state.

Answer 2

In Java, fields that are declared as members of an interface are implicitly static and final . Therefore, these members are not part of your object instance and therefore PageFactory.initElements doesn't initialize them.

The same should happen also without using an interface - all @findBy annotations on static members will be ignored.