Handling Alerts using selenium webdriver

/ /How to handle alerts in Selenium

import org.openqa.selenium.Alert;
import org.openqa.selenium.By;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.firefox.FirefoxDriver;

public class HandlingAlerts {

 public static void main(String[] args) throws InterruptedException {
  WebDriver driver = new FirefoxDriver();
  String Url = "ur url";
  driver.get(Url);
  WebElement alert = driver.findElement(By.xpath("html/body/div[1]/center/table/tbody/tr/td/form[1]/p/input"));
  alert.click();
  Alert popup = driver.switchTo().alert();
  System.out.println(popup.getText());
popup.accept();
  Thread.sleep(3000);
  
  driver.close();

  
  
 }
}