How to switch from one window to other using selenium webdriver?

//Returns all the available window id’s

Set<String> WINDOWIDS= driver.getWindowHandles();

Iterator<String> iter=WINDOWIDS.iterator();    

String Window1=iter.next();//Returns first window id

String Window2=iter.next();//Returns second window id

driver.switchTo().window(Window2);//Focus will be switched to second window

//Perform actions on Window2

driver.close();//It will close the second window

driver.switchTo().window(Window1);//Focus will be switched to first window

//Perform actions on Window1

driver.close();//It will close the first window