Hello, Please help. I want to submmit a exercise,i have used a program make for me but i don´t know if i am doing something bad, i put four parameters. data.put("code", array); data.put("langid",languageId); data.put("contest", contest_id); data.put("shortname",nombreProblema); This is the code complete from my method: private void testConsumerPOST(String array[], String nombreProblema, String languageId, String contest_id) { String servletURL = "http://192.168.1.146/domjudge/api/submissions"; URL servlet = null; try { servlet = new URL(servletURL); System.out.println("Sending request to " + servletURL); HttpURLConnection servletConnection = (HttpURLConnection) servlet.openConnection(); servletConnection.setRequestMethod("POST"); servletConnection.setDoOutput(true); servletConnection.setDoInput(true); //send the keys to the server OutputStreamWriter out = new OutputStreamWriter(servletConnection.getOutputStream()); ObjectMapper mapper = new ObjectMapper(); //Jackson Object mapper Map<String, Object> data = new HashMap<String, Object>(); data.put("code", array); data.put("langid",languageId); data.put("contest", contest_id); data.put("shortname",nombreProblema); // data.put("teamid",teamId); out.write(mapper.writeValueAsString(data)); //objOut.flush(); //objOut.close(); } catch (MalformedURLException ex) { Logger.getLogger(PostSubmission.class.getName()).log(Level.SEVERE, null, ex); } catch (ProtocolException ex) { Logger.getLogger(PostSubmission.class.getName()).log(Level.SEVERE, null, ex); } catch (IOException ex) { Logger.getLogger(PostSubmission.class.getName()).log(Level.SEVERE, null, ex); } } king regards.