Selenium - org.openqa.selenium.WebDriverException: b is null

Question

I am always getting this below exception while running my tests with Selenium Webdriver.

I have done some Googling but couldn't find anything related to this exception but found that this exception occurs when you are executing JavaScript in your code but I am NOT doing so.

Code throwing this exception:-

public void foo(){
    WebDriver driver = new FirefoxDriver();
    driver.get("www.xyz.com");
    driver.switchTo().defaultContent();
    driver.switchTo().frame(driver.findElement(By.xpath("(//iframe[contains(@id ,'easyXDM_default')])[2]")));
    WebElement resultsDiv = driver.findElement(By.xpath("(//textarea[contains(@id,'ext-comp')])[1]"));
    .....

}

Exception is thrown whenever we are finding the textarea field in the application & the field is inside the frame.

Below is the stack trace:-

org.openqa.selenium.WebDriverException: b is null

Command duration or timeout: 21 milliseconds Build info: version: '2.41.0', revision: '3192d8a6c4449dc285928ba024779344f5423c58', time: '2014-03-27 11:29:39' System info: host: 'HPDA0128', ip: '10.9.60.36', os.name: 'Windows 7', os.arch: 'x86', os.version: '6.1', java.version: '1.7.0_55' Session ID: f228cc09-2dd5-4658-9950-c504bf007b7f Driver info: org.openqa.selenium.firefox.FirefoxDriver Capabilities [{platform=XP, acceptSslCerts=true, javascriptEnabled=true, cssSelectorsEnabled=true, databaseEnabled=true, browserName=firefox, handlesAlerts=true, browserConnectionEnabled=true, webStorageEnabled=true, nativeEvents=false, rotatable=false, locationContextEnabled=true, applicationCacheEnabled=true, takesScreenshot=true, version=30.0}] at sun.reflect.GeneratedConstructorAccessor13.newInstance(Unknown Source) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source) at java.lang.reflect.Constructor.newInstance(Unknown Source) at org.openqa.selenium.remote.ErrorHandler.createThrowable(ErrorHandler.java:193) at org.openqa.selenium.remote.ErrorHandler.throwIfResponseFailed(ErrorHandler.java:145) at org.openqa.selenium.remote.RemoteWebDriver.execute(RemoteWebDriver.java:595) at org.openqa.selenium.remote.RemoteWebDriver.findElement(RemoteWebDriver.java:348) at org.openqa.selenium.remote.RemoteWebDriver.findElementByXPath(RemoteWebDriver.java:445

How can I resolve this error or what does this error signify/mean?

Where is the relevant code? What's on the line that has the error? Have you tried debeugging? — RossC
Yes, I have tried debugging by using try -catch block where I catch the exception & again performed the same action...but the results are the same — Harsh Sehgal
Could you please explain what does this exception mean.... i.e., what does "b" mean over here??? — Harsh Sehgal

Delfalso Delfalso · Accepted Answer · 2018-09-11T11:43:03

I had the same error while trying to click on an element of my webpage. I also tried to use coordinates but had the same error. (Javascript error b is null)

But it finally work by adding a refresh code line before trying to access and click to the element.

Before:

By myBy= By.xpath("//img[contains(@title,'title')]");
driver.findElement(myBy).click();

After:

driver.navigate().refresh();
By myBy= By.xpath("//img[contains(@title,'title')]");
driver.findElement(myBy).click();

Maybe you should try to refresh your page (driver.navigate().refresh();) before trying to access the element.

Selenium - org.openqa.selenium.WebDriverException: b is null

1 Answers