title: What is the difference between sun.reflect.generics.reflectiveObjects.NotImplementedException and org.apache.commons.lang3.NotImplementedException
body: <p>I have discovered there are 2 NotImplementedException:</p>
  
  <ul>
  <li>sun.reflect.generics.reflectiveObjects.NotImplementedException</li>
  <li>org.apache.commons.lang3.NotImplementedException</li>
  </ul>
  
  <p>Since there is not an available documentation for the first one, I'm not able to understand the difference between them.
  What is this difference? Is one of them better than the other one?</p>