When a user asks for a resouce, server sends a response, which is not the actual requested resource. It does by sending repsonse code of 302 and a URL of the requested resource. The browser automatically makes a request with this URL and gets the resource. Thus there is round trip operation between the client and the server. so it should be used in special purposes by using the methods sendRedirect()...
Go through the documents for further understanding..
"R S B", You have already been asked to change your display name here and here.
We're light on rules, but we take display names quite seriously. You can read the full report here, but basically we require your display name to be two words: your first name, a space, then your last name. Fictitious names and initials aren't allowed.
Please edit your profile and correct your display name, since accounts with invalid display names get deleted, often without warning.