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

This code will check whether the alert is present or not.

public static void isAlertPresent(){
    try{
    Alert alert = driver.switchTo().alert();
    System.out.println(alert.getText()+" Alert is Displayed"); 
    }
    catch(NoAlertPresentException ex){
    System.out.println("Alert is NOT Displayed");
    }
    }