Asking PageFactory.initElements() for Help

Some people asked me what kind of things are done by PageFactory.initElements()?
Let's see a simple example to see the difference,PS: code just for Demo, not for formal testing:-):

CommonPage.class(PageObject)

 public class CommonPage {  
      private WebDriver driver;  
      @FindBy(how = How.NAME, using = "q")  
   private WebElement searchtext;  
      @FindBy(how = How.NAME, using = "btnG")  
   private WebElement searchbutton;  
      public CommonPage(WebDriver driver) {  
             this.driver = driver;  
             System.out.println("cool stuff!");  
      }  
      public CommonPage getpages(){  
           driver.get("http://www.google.com/");  
           searchtext.sendKeys("hello, common");  
           return this;  
      }  
      public void searchaction(){  
           searchbutton.click();  
      }  
 }  

Version1, using PageFactory.initElements(WebDriver, Class):
Testcode:

 public class PageFactoryTest {  
      /**  
       * @param args  
       */  
      public static void main(String[] args) {  
           // TODO Auto-generated method stub  
                WebDriver driver = new FirefoxDriver();  
                CommonPage searchpage = PageFactory.initElements(driver, CommonPage.class); 
                searchpage.getpages().searchaction();   
                driver.quit();  
           }  
      }  

Version2, just using New:
Testcode:

 public class PageFactoryTest {  
      /**  
       * @param args  
       */  
      public static void main(String[] args) {  
           // TODO Auto-generated method stub  
                WebDriver driver = new FirefoxDriver();  
                CommonPage searchpage = new CommonPage(driver);  
                searchpage.getpages().searchaction();  
                driver.quit();  
           }  
      }  

So both PageFactory.initElements(driver, CommonPage.class); and new CommonPage(driver); are calling the construct method in order to pass the Driver to Commonpage class.

The difference between these 2 versions is to initialize looking up the WebElement (Fields) you declared in Commonpage.
so if you define your WebElements using @FindBy annotation instead of defining it within your each method directly(eg. driver.findElement(By)), then you need to using PageFactory.initElements() for help.