Из-за чего появляется исключение?

Исключение указывает на эту строку StringuserJsonStroke=getJsonFromServer(String.format("%s/%d", urlPath), 0);

Вот весь класс

public class JsonPlaceholderApi {
    private String urlPath;
    public JsonPlaceholderApi(String urlPath) {
        this.urlPath = urlPath;
    }
    public User getUser(JSONObject jsonObject) throws IOException, JSONException {

//        JSONObject userRoot = new JSONObject(jsonObject);
        JSONObject userAddress = jsonObject.getJSONObject("address");
        JSONObject userCompany = jsonObject.getJSONObject("company");
        JSONObject addressGeo = userAddress.getJSONObject("geo");
        int userId = jsonObject.getInt("id");
        String userName = jsonObject.getString("name");
        String userNameName = jsonObject.getString("username");
        String userEmail = jsonObject.getString("email");
        String userPhone = jsonObject.getString("phone");
        String userWebSite = jsonObject.getString("website");
        String addressStreet = userAddress.getString("street");
        String addressSuite = userAddress.getString("suite");
        String addressCity = userAddress.getString("city");
        String addressZipcode = userAddress.getString("zipcode");
        double geoLat = addressGeo.getDouble("lat");
        double getLon = addressGeo.getDouble("lng");
        String companyName = userCompany.getString("name");
        String companyCatchPhrase = userCompany.getString("catchPhrase");
        String companyBs = userCompany.getString("bs");
        Geo geo = new Geo(geoLat, getLon);
        Address address = new Address(addressStreet, addressSuite, addressCity, addressZipcode, geo);
        Company company = new Company(companyName, companyCatchPhrase, companyBs);
        return new User(userId, userName, userNameName, userEmail, address, userPhone, userWebSite, company);
    }
   public ArrayList<User> getUserList() throws IOException, JSONException {

       String userJsonStroke = getJsonFromServer(String.format("%s/%d", urlPath), 0);
       JSONArray array = new JSONArray(userJsonStroke);
       ArrayList<User> userArrayList = new ArrayList<>();

       for(int i = 0; i<array.length(); i++){
           JSONObject obj = array.getJSONObject(i);
           User newUser = getUser(obj);
           userArrayList.add(newUser);
       }

        return  userArrayList;
    }
    private String getJsonFromServer(String urlPath, int timeout) throws IOException {
        URL url = new URL(urlPath);
        HttpURLConnection connection = (HttpURLConnection) url.openConnection();
        connection.setRequestMethod("GET");
        connection.setConnectTimeout(timeout);
        connection.setReadTimeout(timeout);
        connection.connect();
        int serverResponseCode = connection.getResponseCode();
        switch (serverResponseCode) {
            case 200:
            case 201:
                BufferedReader br = new BufferedReader(new InputStreamReader(connection.getInputStream()));
                StringBuilder sb = new StringBuilder();
                String tmpLine;
                while ((tmpLine = br.readLine()) != null) {
                    sb.append(tmpLine).append("\n");
                }
                br.close();
                return sb.toString();
            case 404:
                Log.d(JsonPlaceholderApi.class.getName(), "page not found!");
                break;
            case 400:
                Log.d(JsonPlaceholderApi.class.getName(), "Bad request!");
                break;
            case 500:
                Log.d(JsonPlaceholderApi.class.getName(), "Internal server error");
                break;
        }
        return null;
    }
}

Сама строчка находится в методе, который парсит json'ы

UserTask class

 public class UserTask extends AsyncTask<Void, Void, Void> {
        @Override
        protected Void doInBackground(Void... voids) {
            JsonPlaceholderApi api = new JsonPlaceholderApi("https://jsonplaceholder.typicode.com/users");
            try {
    //            User user = api.getUser(1);
    //            User user2 = api.getUser(2);
    //            User user3 = api.getUser(3);
                Log.d("Success",(api.getUserList().toString()));
            } catch (IOException e) {
                e.printStackTrace();
            } catch (JSONException e) {
                e.printStackTrace();
            }
            return null;
        }
        @Override
        protected void onPostExecute(Void aVoid) {
            super.onPostExecute(aVoid);
        }
    }