title: google app engine project: Server Error The server encountered an error and could not complete your request
body: <p>when I executed my web app engine project in java for login application it showed this error can any one help
  I am using eclipse kepler java 1.7 in my system 
  I am not getting any exception. enabled data store also.
  Error: Server Error
  The server encountered an error and could not complete your request.</p>
  
  <p>If the problem persists, please report your problem and mention this error message and the query that caused it.</p>