POST request send JSON data Java HttpUrlConnection

Your JSON is not correct. Instead of

JSONObject cred = new JSONObject();JSONObject auth=new JSONObject();JSONObject parent=new JSONObject();cred.put("username","adm");cred.put("password", "pwd");auth.put("tenantName", "adm");auth.put("passwordCredentials", cred.toString()); // <-- toString()parent.put("auth", auth.toString());              // <-- toString()OutputStreamWriter wr= new OutputStreamWriter(con.getOutputStream());wr.write(parent.toString());

write

JSONObject cred = new JSONObject();JSONObject auth=new JSONObject();JSONObject parent=new JSONObject();cred.put("username","adm");cred.put("password", "pwd");auth.put("tenantName", "adm");auth.put("passwordCredentials", cred);parent.put("auth", auth);OutputStreamWriter wr= new OutputStreamWriter(con.getOutputStream());wr.write(parent.toString());

So, the JSONObject.toString() should be called only once for the outer object.

Another thing (most probably not your problem, but I'd like to mention it):

To be sure not to run into encoding problems, you should specify the encoding, if it is not UTF-8:

con.setRequestProperty("Content-Type", "application/json; charset=UTF-8");con.setRequestProperty("Accept", "application/json");// ...OutputStream os = con.getOutputStream();os.write(parent.toString().getBytes("UTF-8"));os.close();

private JSONObject uploadToServer() throws IOException, JSONException {            String query = "https://example.com";            String json = "{\"key\":1}";            URL url = new URL(query);            HttpURLConnection conn = (HttpURLConnection) url.openConnection();            conn.setConnectTimeout(5000);            conn.setRequestProperty("Content-Type", "application/json; charset=UTF-8");            conn.setDoOutput(true);            conn.setDoInput(true);            conn.setRequestMethod("POST");            OutputStream os = conn.getOutputStream();            os.write(json.getBytes("UTF-8"));            os.close();            // read the response            InputStream in = new BufferedInputStream(conn.getInputStream());            String result = org.apache.commons.io.IOUtils.toString(in, "UTF-8");            JSONObject jsonObject = new JSONObject(result);            in.close();            conn.disconnect();            return jsonObject;    }

You can use this code for connect and request using http and json

try {                 URL url = new URL("https://www.googleapis.com/youtube/v3/playlistItems?part=snippet"                + "&key="+key                + "&access_token=" + access_token);        HttpURLConnection conn = (HttpURLConnection) url.openConnection();        conn.setDoOutput(true);        conn.setRequestMethod("POST");        conn.setRequestProperty("Content-Type", "application/json");         String input = "{ \"snippet\": {\"playlistId\": \"WL\",\"resourceId\": {\"videoId\": \""+videoId+"\",\"kind\": \"youtube#video\"},\"position\": 0}}";         OutputStream os = conn.getOutputStream();        os.write(input.getBytes());        os.flush();         if (conn.getResponseCode() != HttpURLConnection.HTTP_CREATED) {            throw new RuntimeException("Failed : HTTP error code : "                + conn.getResponseCode());        }         BufferedReader br = new BufferedReader(new InputStreamReader(                (conn.getInputStream())));         String output;        System.out.println("Output from Server .... \n");        while ((output = br.readLine()) != null) {            System.out.println(output);        }         conn.disconnect();       } catch (MalformedURLException e) {         e.printStackTrace();       } catch (IOException e) {         e.printStackTrace();      }