How to check if an alert exists using WebDriver?

Question

I need to check the existence of Alert in WebDriver.

Sometimes it pops up an alert but sometimes it will not pop up. I need to check if the alert exists first, then

Answer 1

I would suggest to use ExpectedConditions and alertIsPresent(). ExpectedConditions is a wrapper class that implements useful conditions defined in ExpectedCondition interface.

WebDriverWait wait = new WebDriverWait(driver, 300 /*timeout in seconds*/);
if(wait.until(ExpectedConditions.alertIsPresent())==null)
    System.out.println("alert was not present");
else
    System.out.println("alert was present");