title: How to check for emptiness of a numeric cell in Apache POI?
body: <p>All is in the title.</p>
  
  <p>How can I check if a <code>CELL_TYPE_NUMERIC</code> is empty with POI ?
  With strings i can use the <code>isEmpty()</code> method but with <code>int</code> I have no ideas (null is not allowed and zero just wont do it).</p>
  
  <p>Thank you in advance.</p>