@Nullable
    @WorkerThread
    public static String getUserUUID(@NonNull final OCApiConnector connector, @NonNull final String userName) {
        //try username as id
        JSONResult result = getRequest(connector, OkapiService.SERVICE_USER_BY_USERID, new Parameters("fields", USER_UUID, USER_INTERNAL_ID, userName));
        if (!result.isSuccess) {
            //try username as username
            result = getRequest(connector, OkapiService.SERVICE_USER_BY_USERNAME, new Parameters("fields", USER_UUID, USER_USERNAME, userName));
            if (!result.isSuccess) {
                final OkapiError error = new OkapiError(result.data);
                Log.e("OkapiClient.getUserUUID: error getting user info via id or username: '" + error.getMessage() + "'");
                return null;
            }
        }

        return result.data.path(USER_UUID).asText(null);
    }
Return a pipe-separated list of preferred languages. English and the device default language (if different) will
always be in the list. A user-set language will be first (if set).
main/src/main/java/cgeo/geocaching/connector/oc/OkapiClient.java