How to execute selenium webdriver tes script parallel in multiple browser using testng parameter annotation.

import org.openqa.selenium.WebDriver;
import org.openqa.selenium.chrome.ChromeDriver;
import org.openqa.selenium.firefox.FirefoxDriver;
import org.openqa.selenium.ie.InternetExplorerDriver;
import org.testng.annotations.AfterMethod;
import org.testng.annotations.BeforeMethod;
import org.testng.annotations.Parameters;
import org.testng.annotations.Test;
public class MultiBrowser {
 private WebDriver driver;

 @Parameters("browser")
 @BeforeMethod
 public void setup(String browser)
 {
  if(browser.equalsIgnoreCase("firefox"))
  {
   driver = new FirefoxDriver();
  }
  else if(browser.equalsIgnoreCase("iexplorer"))
  {
// Update the driver path with your location
   System.setProperty("webdriver.ie.driver", "Drivers\\IEDriverServer.exe");
   driver = new InternetExplorerDriver();
  }
  else if(browser.equalsIgnoreCase("chrome"))
  {
// Update the driver path with your location
   System.setProperty("webdriver.chrome.driver", "Drivers\\chromedriver.exe");
   driver = new ChromeDriver();
  }
  driver.manage().window().maximize();
 }

 @AfterMethod
 public void tearDown()
 {
 driver.quit();
 }

 @Test
 public void testMultiBrowser() throws InterruptedException
 {
  driver.get("http://www.google.com");
  Thread.sleep(3000);
 }
}

2. Now we need to create TestNG.xml and write the following code:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE suite SYSTEM "http://testng.org/testng-1.0.dtd" >
<suite name="MultiBrowser">
       <test name="TestFirefox" verbose="10">
              <parameter name="browser" value="firefox" />
              <classes>
                     <class name="MultiBrowser" />
              </classes>
       </test>
       <test name="ChromeTest">
              <parameter name="browser" value="chrome" />
              <classes>
                     <class name="MultiBrowser" />
              </classes>
       </test>
       <test name="IETest">
              <parameter name="browser" value="iexplorer" />
              <classes>
                     <class name="MultiBrowser" />
              </classes>
       </test>
</suite>

3. Now run the code from TestNG.xml

You can observer all the three browsers will open and perform the task at a time.