title: Retrofit 2 sending duplicated parameters
body: <p>I'm using retrofit in my app to send a POST request, but the parameters are being sent twice and I can't find the reason.</p>
  
  <p>This is my api:</p>
  
  <pre><code>public interface ChoferesApi {
      @POST("myurl/")
      Call&lt;Chofer&gt; registroChofer(@Body Chofer chofer);
  }
  </code></pre>
  
  <p>My POJO object:</p>
  
  <pre><code>public class Chofer {
    private String apellido;
    private String nombre;
    private String email;
    private int dni;
    private String sexo;
    private Date fechaNacimiento;
    private String password;
  
    //Getters &amp; Setters...
  </code></pre>
  
  <p>}</p>
  
  <p>The request:</p>
  
  <pre><code>Call&lt;Chofer&gt; call = RestClient.getInstance().registroChofer(chofer);
  call.enqueue(new Callback&lt;Chofer&gt;() { ... });
  </code></pre>
  
  <p>In logcat I only see the parameters once (according to okhttp):</p>
  
  <pre><code>    11-09 18:46:53.170 27197-27742/com.mypackage D/OkHttp: --&gt; POST http://192.168.1.5:3000/myurl http/1.1
      11-09 18:46:53.170 27197-27742/com.mypackage D/OkHttp: Content-Type: application/json; charset=UTF-8
      11-09 18:46:53.170 27197-27742/com.mypackage D/OkHttp: Content-Length: 139
      11-09 18:46:53.170 27197-27742/com.mypackage D/OkHttp: {"apellido":"aaa","sexo":"masculino","email":"a@a.com","fecha_nacimiento":"2016-10-09","nombre":"aaa","password":"effdggffy","dni":1234564}
      11-09 18:46:53.170 27197-27742/com.mypackage D/OkHttp: --&gt; END POST (139-byte body)
  </code></pre>
  
  <p>But in my server, the following parameters are received:</p>
  
  <pre><code>Started POST "/myurl" for 192.168.1.13 at 2016-11-09 16:39:05 -0300
  Cannot render console from 192.168.1.13! Allowed networks: 127.0.0.1, ::1, 127.0.0.0/127.255.255.255
  Processing by MyController#myaction as HTML
  Parameters: {"apellido"=&gt;"gh", "sexo"=&gt;"masculino", "email"=&gt;"a@a.com", "fecha_nacimiento"=&gt;"2016-10-09", "nombre"=&gt;"ggg", "password"=&gt;"[FILTERED]", "dni"=&gt;54577457, "registro"=&gt;{"apellido"=&gt;"gh", "sexo"=&gt;"masculino", "email"=&gt;"a@a.com", "fecha_nacimiento"=&gt;"2016-10-09", "nombre"=&gt;"ggg", "password"=&gt;"[FILTERED]", "dni"=&gt;54577457}}
  </code></pre>
  
  <p>As can be seen, the parameters are being sent twice, the second time inside an object called "registro" and I can't figure out why. I tried sending the same request using POSTMAN and the parameters are only sent once, so this is NOT a server-side issue.</p>