title: JSF Email Validation - Do not allow domains like yahoo, gmail, etc to be accepted
body: <p>I already have an email validator that works alright to check format of emails in the form of regular expression.</p>
  
  <p>Now - I want to write another email validator in Java (since my application is on JSF, Glassfish 3.x) that <strong>does not allow non-government emails</strong> to be entered in the textbox. All domains like yahoo, gmail, hotmail etc. should not be accepted.  </p>
  
  <p>It should only accept Indian government domain based emails - <code>@gov.in</code>, <code>@nic.in</code> - all other emails should be rejected and the user should be suitably informed.</p>
  
  <p>Requesting help in this regard. Thanks in advance.</p>