Runing test script in multiple browsers using WebDriver

TestNG :

http://testng.org/testng-1.0.dtd">
<suite name="Parallel test suite">
  <test name="Firefox Test">
  <parameter name="browser" value="firefox"/>
    <classes>
      <class name="com.pack.ParallelTest"/>
    </classes>
  </test>
  <test name="Chrome Test">
  <parameter name="browser" value="chrome"/>
    <classes>
      <class name="com.pack.ParallelTest"/>
    </classes>
  </test>
    <test name="Internet Explorer Test">
    <parameter name="browser" value="iexplore"/>
    <classes>
      <class name="com.pack.ParallelTest"/>
    </classes>
  </test>
</suite> 

Write your Java WebDriver code as below:

@Parameters({"browser"})

@BeforeClass

public void setUp(String browser) {

           if(browser.equalsIgnoreCase("iexplore")){

              driver = new InternetExplorerDriver();

           }

           if(browser.equalsIgnoreCase("firefox")){

              driver = new FirefoxDriver();

           }

           if(browser.equalsIgnoreCase("chrome")){  

              driver = new ChromeDriver();

           }

         

           driver.manage().window().maximize();

     

       }