*
     * @return The configured SPNEGO authenticator instance
     * @throws SsoLoginException if SPNEGO initialization fails
     */
    protected synchronized org.codelibs.spnego.SpnegoAuthenticator getAuthenticator() {
        final FessConfig fessConfig = ComponentUtil.getFessConfig();
        if (authenticator != null && fessConfig.getSystemPropertyAsBoolean(SPNEGO_INITIALIZED, false)) {
            return authenticator;