title: Using Enum constant in request header spring boot
body: <p>I have a spring boot application and want to use an Enum constant to specify the value as shown below, however, the compiler generates an error 
  "Type mismatch: cannot convert from Constants to String"
  Here is the code block</p>
  
  <pre><code>@RequestMapping(method= RequestMethod.POST, value="/user")
  public User createUser(@RequestBody User user,
          @RequestHeader(value= Constants.HEADER_USER_AGENT) String userAgent
  )
  </code></pre>
  
  <p>I know I can use public static String instead of Enum, but I wonder if it is possible to use Enum constants?</p>