try this:-
WebDriver driver =new FirefoxDriver();
driver.get("URL");
Robot rb = new Robot();
//Enter user name by ctrl-v
StringSelection username = new StringSelection("username");
Toolkit.getDefaultToolkit().getSystemClipboard().setContents(username, null);
rb.keyPress(KeyEvent.VK_CONTROL);
rb.keyPress(KeyEvent.VK_V);
rb.keyRelease(KeyEvent.VK_V);
rb.keyRelease(KeyEvent.VK_CONTROL);
//tab to password entry field
rb.keyPress(KeyEvent.VK_TAB);
rb.keyRelease(KeyEvent.VK_TAB);
Thread.sleep(2000);
//Enter password by ctrl-v
StringSelection pwd = new StringSelection("password");
Toolkit.getDefaultToolkit().getSystemClipboard().setContents(pwd, null);
rb.keyPress(KeyEvent.VK_CONTROL);
rb.keyPress(KeyEvent.VK_V);
rb.keyRelease(KeyEvent.VK_V);
rb.keyRelease(KeyEvent.VK_CONTROL);
//press enter
rb.keyPress(KeyEvent.VK_ENTER);
rb.keyRelease(KeyEvent.VK_ENTER);
Using robot classes you can handle popup.
Hope this will help you!!!
Try this:-
ChromeOptions options = new ChromeOptions();
options.addArguments("start-maximized");
options.addArguments("disable-infobars");
options.addArguments("--disable-extensions");
WebDriver driver = new ChromeDriver(options);
driver.navigate().to("http://admin:admin@the-internet.herokuapp.com/basic_auth");