*
     * @return The admin environment for LDAP connection.
     */
    protected Hashtable<String, String> createAdminEnv() {
        return createEnvironment(//
                fessConfig.getLdapInitialContextFactory(), //
                fessConfig.getLdapSecurityAuthentication(), fessConfig.getLdapProviderUrl(), //
                fessConfig.getLdapAdminSecurityPrincipal(), //

    }

    default void setLdapInitialContextFactory(final String value) {
        setSystemProperty(Constants.LDAP_INITIAL_CONTEXT_FACTORY, value);
    }

    default String getLdapInitialContextFactory() {
        return getSystemProperty(Constants.LDAP_INITIAL_CONTEXT_FACTORY, "com.sun.jndi.ldap.LdapCtxFactory");
    }

    default void setLdapSecurityAuthentication(final String value) {