title: Is StringUtils.isNumeric() method specification logically correct?
body: <p>Apache's <code>StringUtils.isNumeric()</code> method specification says:<br>
  Checks if the String contains only unicode digits. A decimal point is not a unicode digit and returns <code>false</code>.
  <code>Null</code> will return <code>false</code>. An empty <code>String ("")</code> will return <code>true</code>.</p>
  
  <p>Is this logically right?
  Why do they see empty string as numeric?</p>