title: Producing application/octet-stream and application/json
body: <p>I have an endpoint that typically returns a document of type PDF, Word, etc. There is user input that goes along with this endpoint, however so I would like to validate it.</p>
  
  <p>The trouble is, when I validate the input and want to return some sort of error JSON response, I end up getting errors similar to </p>
  
  <p><code>
  Failed executing GET /foo/generateBar: NoMessageBodyWriterFoundFailure: Could not find MessageBodyWriter for response object of type: FooResponse of media type: application/octet-stream
  </code></p>
  
  <p>What I am using on my endpoint is <code>@Produces({"application/octet-stream", "application/json"})</code></p>
  
  <p>Is there a way I can avoid this error by possibly returning both JSON and different file formats? My impression is that what the <code>@Produces</code> I was using was doing, however I'm probably thoroughly confused.</p>
  
  <p>Additionally, I must note that I'm using <code>window.open</code> on the front-end side to call this endpoint.</p>