title: How to validate a gmail address in Java
body: <p>How can I verify if a given gmail address is valid or not?</p>
  
  <p>I'm not asking for a script to check validation nor any regular expression. I only need to know if a person put a valid gmail address in a verify box. Some code which checks Google's database to see if it is a valid gmail address. The same as when we register a new gmail address and it shows a message saying the gmail address already exists. If it is possible to do so with some Google API for Java? I would like to use it in GAE.</p>