Invalid "Content-Type" from Java code but works in Postman

Question

I am trying to send a POST request to a particular URL, below is my Java Code to do it...

            OkHttpClient httpClient = new OkHttpClient().newBuilder().build();
            
            MediaType JSON = MediaType.parse("application/json; charset=utf-8");
            
            RequestBody body = RequestBody.create("<JSON_AS_STRING>", JSON);
            
            Request request = new Request.Builder()
              .url(url)
              .method("POST", body)
              .addHeader("Authorization", getToken())
              .addHeader("Content-Type", "application/json; charset=utf-8")
              .build();

            Response response = httpClient.newCall(request).execute()

When the request is excuted I am getting "Invalid content type" under error code 100. I am storing the JSON Body in a string and using it and defining media type to create a body.

But when I send same request from Postman, I am getting success code 204.

In Postman I have selected body as JSON and passing the JSON in the body and setting the URL and other headers like authorization and when I am sending the request I am getting 204.

But when I change it to text, then I get same error "Invalid content type" which I am getting from my Java code. I am using OkHttp3 library for client, request and response. How is my java code not taking media type as application/json. I even tried to pass "charset=utf-8" in header with application/json, still not working.

Any suggestions what could be going wrong, this is not the first time I am creating an okhttp3 request but first time seeing something like this...

Also I even tried to copy the java code snipped which you can create using postman...still not working.

Answer 1

Can you log the entire incoming request (header and payload) on the server? That way you would see if they differ in any way. Another thing I'd try is sending the request using a low-level tool like cURL instead of Postman.

(Courtesy: How do I POST JSON data with cURL? )

curl  http://localhost:8080/api/login  -H "content-type: application/json"  -d "{\"email\": \"user@admin.com\", \"password\": \"123456\"}"

You can also etract the cURL command from Postman itself

Answer 2

I found the problem, when you set MediaType, then "charset=utf-8" was getting added which was leading to the error that I mentioned. So I removed the "charset=utf-8" manually and tried to send the request, this time I was using fiddler to listen to request sent from eclipse, turns out, whether you pass that charset or not, the MediaType will append it, so I tried to set the second parameter on MediaType.parse() as null, and just passed the header with Content Type as application/json, and it worked like a charm.