How to run script on firefox, chrome and IE parallaly on Selenium Webdriver using java?.

 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.openqa.selenium.remote.DesiredCapabilities;  
 public class FirefoxchromeIEbrowser {  
   static WebDriver fireFoxDriver = null;  
   static WebDriver chromeDriver = null;  
   static WebDriver internetExplorerDriver = null;  
   public static void main(String[] arg) {  
     //create firefox instance  
     fireFoxDriver = new FirefoxDriver();  
     //Maximize browser window     
     fireFoxDriver.manage().window().maximize();  
     //Go to URL   
     fireFoxDriver.get("http://www.yahoo.com");     
     //close FireFox browser   
     fireFoxDriver.quit();  
     ////set chrome driver path  
     System.setProperty("webdriver.chrome.driver", System.getProperty("user.dir") + "\\chromedriver.exe");  
     //create chrome instance  
     chromeDriver = new ChromeDriver();  
     //Maximize browser window     
     chromeDriver.manage().window().maximize();  
     //Go to URL  
     chromeDriver.get("http://www.gmail.com");  
     //close Chome browser   
     chromeDriver.quit();  
     ////set IE driver path  
     System.setProperty("webdriver.ie.driver", System.getProperty("user.dir") + "\\IEDriverServer.exe");  
     System.out.println(System.getProperty("user.dir") + "\\IEDriverServer.exe");  
     //create IE instance  
     internetExplorerDriver = new InternetExplorerDriver();  
     //Maximize browser window   
     internetExplorerDriver.manage().window().maximize();  
     //Go to URL  
     internetExplorerDriver.get("http://www.google.com/");  
     //close IE browser   
     internetExplorerDriver.quit();  
   }  
 }