@Override
    public String getXMPPDomain()
    {
        return Optional.ofNullable(XMPP_DOMAIN.getValue()).orElse(getHostname()).toLowerCase();
    }
Simple constructor

@param startDate the server's last start time (can be null indicating
     it hasn't been started).
xmppserver/src/main/java/org/jivesoftware/openfire/spi/XMPPServerInfoImpl.java