title: Never use public nested enums?
body: <p>I recently came across a coding standard claiming that you should <strong>never</strong> use <em>public</em> inner enums/classes in Java. This is the first time I've encountered this convention, and haven't been able to find a satisfactory explaniation as to why.</p>
  
  <p>I understand why public inner classes should be avoided, but for what reasons would you never use public nested enums? Or, why is this a bad convention to follow?</p>