title: When to use Enum or Collection in Java
body: <p>Under what circumstances is an enum more appropriate than, for example, a Collection that guarantees unique elements (an implementer of java.util.Set, I guess...)?</p>
  
  <p>(This is kind of a follow up from my previous <a href="https://stackoverflow.com/questions/478403/can-i-add-and-remove-elements-of-enumeration-at-runtime-in-java">question</a>)</p>