title: MongoDB: WriteResult.getN() always returns 0?
body: <p>According to the <a href="http://api.mongodb.org/java/current/com/mongodb/WriteResult.html#getN%28%29" rel="noreferrer">javaDoc</a>, <code>getN()</code> method of <code>WriteResult</code> class in MongoDB-java returns the number of documents updated in the opertion.
  But it always returns zero, even if the document is inserted correctly.</p>
  
  <p>Why so? or I understood it wrongly?</p>