title: Should a retrieval method return 'null' or throw an exception when it can't produce the return value?
body: <p>I am using java language,I have a method that is supposed to return an object if it is found.</p>
  <p>If it is not found, should I:</p>
  <ol>
  <li>return null</li>
  <li>throw an exception</li>
  <li>other</li>
  </ol>
  <p>Which is the best practise or idiom?</p>