@Override
  public Map<UUID, String> call() throws Exception {
    Map<UUID, String> uuidStringMap = new HashMap<UUID, String>();
    for (UUID uuid : uuids) {
      HttpURLConnection
          connection =
          (HttpURLConnection) new URL(PROFILE_URL + uuid.toString().replace("-", ""))
              .openConnection();
      JSONObject
          response =
          (JSONObject) jsonParser.parse(new InputStreamReader(connection.getInputStream()));
      String name = (String) response.get("name");
      if (name == null) {
        continue;
      }
      String cause = (String) response.get("cause");
      String errorMessage = (String) response.get("errorMessage");
      if (cause != null && cause.length() > 0) {
        throw new IllegalStateException(errorMessage);
      }
      uuidStringMap.put(uuid, name);
    }
    return uuidStringMap;
  }