grant_type=password
password=qwerty
username=administrator

public JSONObject getLoginToken(String username, String password) {
        URL url = null;
        HttpURLConnection httpURLConnection = null;
        BufferedReader bufferedReader = null;
        JSONObject response = null;

        try {
            url = new URL("someUrl");
            httpURLConnection = (HttpURLConnection) url.openConnection();

            JSONObject data = new JSONObject();
            data.put("username", username);
            data.put("password", password);
            data.put("grant_type", "password");

            httpURLConnection.setChunkedStreamingMode(0);
            httpURLConnection.setRequestMethod("POST");
            httpURLConnection.setDoOutput(true);
            httpURLConnection.setDoInput(true);

            httpURLConnection.connect();

            OutputStream os = httpURLConnection.getOutputStream();
            BufferedWriter writer = new BufferedWriter(
                    new OutputStreamWriter(os, "UTF-8"));
            writer.write(URLEncoder.encode(data.toString(), "UTF-8"));
            writer.flush();
            writer.close();
            os.close();

            bufferedReader = new BufferedReader(new InputStreamReader(httpURLConnection.getInputStream())); // <-- fails here

            StringBuilder sb = new StringBuilder();
            String line = null;

            while ((line = bufferedReader.readLine()) != null) {
                sb.append(line + "n");
            }

            response = new JSONObject(sb.toString());
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (JSONException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (httpURLConnection != null) {
                httpURLConnection.disconnect();
            }
        }

        return response;
    }