title: Use enum like a getter?
body: <p>I have a util class that keeps track of important system variables:</p>
  
  <pre><code>public static final String REQUEST_ADDRESS = "http.request.address";  
  public static final String REQUEST_PORT = "http.request.port";
  
  public static final String get(String property) {
      return System.getProperty(property);
  }
  </code></pre>
  
  <p>And I can retrieve these values like so:</p>
  
  <pre><code>String port = SystemPropertyHelper.get(SystemPropertyHelper.REQUEST_PORT);
  </code></pre>
  
  <p>Is it possible, in Java, to get these like an enum?</p>
  
  <pre><code>REQUEST_PORT {
      return System.getProperty("http.request.port");
  }
  
  String port = SystemPropertyHelper.REQUEST_PORT;
  </code></pre>