How to handle JavaScript alerts or dialog boxes

gistfile1.java

import java.util.concurrent.TimeUnit;
import org.openqa.selenium.*;
import org.openqa.selenium.firefox.FirefoxDriver;


public class JavaScriptPopups 
{
	public static void main(String[] args) 
	{
		WebDriver driver=new FirefoxDriver();

		//Demonstration of Alert Box
		driver.get("file:///E:/Programming%20Samples/HTML%20Samples/AlertBoxEx.html");
		driver.manage().timeouts().implicitlyWait(10, TimeUnit.SECONDS);

		driver.findElement(By.name("clickMe")).click();
		Alert alert=driver.switchTo().alert();
		System.out.println(alert.getText());
		alert.accept();
		driver.close();
		
		//Demonstration of Conformation Box
		driver.get("file:///E:/Programming%20Samples/HTML%20Samples/ConformationBoxEx.html");
		driver.manage().timeouts().implicitlyWait(10, TimeUnit.SECONDS);

		driver.findElement(By.name("clickMe")).click();
		Alert alert=driver.switchTo().alert();
		System.out.println(alert.getText());
//		alert.accept();
		alert.dismiss();
//		driver.close();

		
		
		//Demonstration of Popup
		driver.get("file:///E:/Programming%20Samples/HTML%20Samples/PopUpEx.html");
		driver.manage().timeouts().implicitlyWait(10, TimeUnit.SECONDS);

		driver.findElement(By.name("clickMe")).click();
		Alert alert=driver.switchTo().alert();
		System.out.println(alert.getText());
		alert.sendKeys("Uday");
//		alert.accept();
		alert.dismiss();
//		driver.close();
		
	}

}