title: Enum for key name and value
body: <p>I want to use Enum as a key value. I tired this:</p>
  
  <pre><code>public interface ElementTypeEnum
  {
      public static String QUEUE_TRANSACTION = "queue_transaction";
  
      public static String QUEUE_API_ATTEMPT = "queue_api_attempt";
  }
  </code></pre>
  
  <p>but when I tried to use it this way: <code>QUEUE_TRANSACTIONs cannot be resolved or is not a field</code></p>
  
  <p>What is the proper way to use it?</p>