java.lang.ClassCastException: com.sun.proxy.$Proxy8 cannot be cast to org.openqa.selenium.internal.WrapsDriver

aspectj, java, webdriver

Solution

While the answer flagged as correct does point out the issue, it doesn't explain the issue nor suggests a solution which does actually exist. Let me begin with giving a bit more of detail around the underlying issue here which is the way the `WebElement` could have been instantiated.

On one hand, when a `WebElement` gets instantiated as the result of a call to `WebDriver#findElement`, the actual `RemoteWebElement` object gets constructed at that very moment, however, when a `WebElement` gets instantiated via `PageFactory#initElements`, the actual concrete class object (`RemoteWebElement`) doesn't get created at that point but instead a proxy does.

Here is where the main issue relies. The proxy object does NOT implement the `WrapsDriver` interface and that is why the cast exception is thrown, which is perfectly fine. However, if you are curious enough to see how the actual proxy creation is done (at least by the default decorator), you will see that the object instantiated as the proxy does instead implement the `WrapsElement` interface which does offer the method `getWrappedElement` so, with it, you can extract the underlying `WebElement` and then with this, extract the underlying `WebDriver`, just as you are trying.

Now, the key here is that any `WebElement` instantiated via `WebDriver#findElement` does not implement `WrapsElement` because it is the actual element and not a proxy so, before you attempt using `WrapsElement#getWrappedElement`, you first need to check if the passed `WebElement` is actually a proxy or not.

You can achieve this with reflection, i.e.

if(WrapsElement.class.isAssignableFrom(element.getClass()))
  webDriver = ((WrapsDriver)((WrapsElement)element).getWrappedElement()).getWrappedDriver();
else
  webDriver = ((WrapsDriver)element).getWrappedDriver();

tl;dr The `WebElement` instance you are using was instantiated via `PageFactory#initElements` and you first need to extract the underlying `WebElement` with `WrapsElement#getWrappedElement` and then the `WebDriver` from it.

Problem

I have following pointcut and the given advice in AspectJ ``` @Pointcut("(call(* org.openqa.selenium.WebElement.sendKeys(..)))") public void onWebElementAction() { } @After("onWebElementAction() && target(webelement)") public void afterWebElementAction(JoinPoint joinPoint, WebElement webelement) { System.out.println(webelement.getAttribute("name")); //1 WebDriver driver = ((WrapsDriver) webelement).getWrappedDriver(); //2 //DO SOMETHING HERE } ``` While the line 1 is executed without any error. It is on line 2 I get error ``` java.lang.ClassCastException: com.sun.proxy.$Proxy8 cannot be cast to org.openqa.selenium.internal.WrapsDriver ``` The casting works in other places without issues. Can someone please help?

Original source