How to authenticate alert popup using Selenium

 Solution :

Use the following code. Example is given in using Firefox.

String url = "https://dev20.***********.com/************";

String username = "s*****";

String password = "e******";

System.setProperty("webdriver.gecko.driver",

"Geckodriver\\v0.21.0-win64\\geckodriver.exe");

WebDriver driver = new FirefoxDriver();

String urlTemp = url.replaceFirst("https://", "");

String URL = "https://" + username  + ":" + password + "@" + urlTemp;

driver.get(URL);

...............................................................................................................

My failed attempt #01:

The following code didn't for me & provide Error:  "org.openqa.selenium.UnsupportedCommandException: POST /session/ef0fb2c1-e4c1-4d63-bab7-6a8fbe03af8b/alert/credentials did not match a known command"

String url = "https://dev20.***********.com/************";

String username = "s*****";

String password = "e******";

System.setProperty("webdriver.gecko.driver",  "Geckodriver\\v0.21.0-win64\\geckodriver.exe");

WebDriver driver = new FirefoxDriver();

driver.get(url);

Alert alertObj = driver.switchTo().alert();

alertObj.authenticateUsing(new UserAndPassword(username, password));

alertObj.accept();

My failed attempt #02:

The following code didn't for me & provide Error:  "org.openqa.selenium.UnsupportedCommandException: POST /session/ef0fb2c1-e4c1-4d63-bab7-6a8fbe03af8b/alert/credentials did not match a known command"

String url = "https://dev20.***********.com/************";

String username = "s*****";

String password = "e******";

System.setProperty("webdriver.gecko.driver",

"Geckodriver\\v0.21.0-win64\\geckodriver.exe");

WebDriver driver = new FirefoxDriver();

driver.get(url);

WebDriverWait wait = new WebDriverWait(driver, 10);      

Alert alertObj = wait.until(ExpectedConditions.alertIsPresent()); 

alertObj.authenticateUsing(new UserAndPassword(username, password));

alertObj.accept();