How to handle Window popups in selenium webdriver

Hi frnds,

I wrote code to handle window popups in selenium webdriver Junit framework. But I am unable to identify the opened popup.

Please find the following code,

getObject("btnAttachFile").click();

String parentWindowHandle = driver.getWindowHandle();
System.out.println("Parent Window Handle: "+parentWindowHandle);
Set s=driver.getWindowHandles();
System.out.println("Handle 'S' Size:" +s.size());
Iterator ite=s.iterator();
if (s.size()==2)
{
// For loop for modal popup
while(ite.hasNext())
{
String popupHandle=ite.next().toString();
String mm=driver.switchTo().window(popupHandle).getTitle();
if ((driver.switchTo().window(popupHandle).getTitle()).equals("Attach FIle"))
{

System.out.println("Modal popup:"+driver.getTitle());
}
}
}
Please verify the above code and suggest me.

Thanks in Advance,