return null;
        }
    }


    /**
     * {@inheritDoc}
     *
     * @see jcifs.smb.SmbRenewableCredentials#renew()
     */
    @Override
    public CredentialsInternal renew () {
        log.debug("Renewing credentials");
        this.cachedSubject = null;
        getSubject();
        return this;
    }


    /**
     * {@inheritDoc}