title: How is this JAX-RS webservice working?
body: <p>I'm going over few pieces of code and came across something like this</p>
  
  <pre><code>@POST
  @Consumes(MediaType.APPLICATION_FORM_URLENCODED)
  @Produces({ MediaType.APPLICATION_JSON , MediaType.APPLICATION_XML })
  public Response getMedia(
          @HeaderParam("X-META") String metaToken,
          @QueryParam("provider") String provider, MultivaluedMap&lt;String, String&gt; formContext ,
          @Context UriInfo uriInfo) {
      Map&lt;String, String&gt; context = APIUtils.buildContext(formContext);
      return getMediaInternal(metaToken, provider, context, uriInfo);
  }
  </code></pre>
  
  <p>I know that Annotated vars are injected by jersey but I'm clueless as how the formContext is being injected. It's not annotated. What all values are put in here by jersey ? All the post parameters ? Whats a general rule to deduce whats being populated when not annotated ? Any pointers to reference material or a brief description of whats happening here is helpful</p>