title: What's the use of creating an enum without instance?
body: <p>I was reading and implementing scenario's through enum. I figured out we can create an enum
  without any instance. What is the practical use of such an <code>Enum</code>? Secondly <code>Enum</code> can also implement
  an interface, but obviously can't extend a class as it already extends class <code>Enum</code>. What are practical  advantages of creating an <code>Enum</code> without instances?
  Ben</p>