title: PlayFramework returns BadRequest with content-type application/json
body: <p>I am facing problem with play framework where sending <code>application/json</code> in content-type header returns a <code>BadRequest</code>.
  I have a controller POST method that needs a few headers for the server to calculate the right hmac value, one of the headers is content-type
  When I send <code>application/json</code> as the <code>content-type</code> I get a Badrequest , it works for <code>application\/json</code> , but the problem is I need to have application/json to compute the correct hmac value.</p>
  
  <p>I have tried with Curl, Poster and a Java client and I am facing the same issue everywhere, I have a test case written in Scala which sends application/json which works(but that is running against a MockController and a FakeRequest).</p>
  
  <p>Adding Some code </p>
  
  <p>This is how I am adding the content-type header <code>httpPost.addHeader(HttpHeaders.CONTENT_TYPE, "\"application/json\""); </code>
  or 
  <code>httpPost.addHeader(HttpHeaders.CONTENT_TYPE, "application\/json");</code>
   either of the two work but plain application/json doesn't</p>
  
  <p>This is the controller Method I am calling </p>
  
  <pre><code>def test() = Action {
  implicit request =&gt;
    Ok("yippiie")
  }
  </code></pre>
  
  <p>Also I tried both with a valid json body and an empty json , got BadRequest in both scenarios with application/json as the content-type header.</p>