if (domains == null) {
            return false;
        }
        domain = domain.toLowerCase();
        return domains.get(domain) != null;
    }

    /**
     * Gets a domain controller transport for the specified domain
     * @param domain the domain name
     * @param auth the authentication credentials
     * @return an SMB transport to the domain controller

            }
            rpc.domains = new lsarpc.LsarRefDomainList();
            rpc.domains.count = 1;
            rpc.domains.max_count = 1;
            rpc.domains.domains = new lsarpc.LsarTrustInformation[1];
            rpc.domains.domains[0] = new lsarpc.LsarTrustInformation();
            rpc.domains.domains[0].name = new UnicodeString("", false);
            rpc.domains.domains[0].sid = new jcifs.dcerpc.rpc.sid_t();

        public LsarTrustInformation[] domains;
        /** Maximum count of domains. */
        public int max_count;

        @Override
        public void encode(NdrBuffer _dst) throws NdrException {
            _dst.align(4);
            _dst.enc_ndr_long(this.count);
            _dst.enc_ndr_referent(this.domains, 1);
            _dst.enc_ndr_long(this.max_count);

            if (this.domains != null) {

        synchronized (this.domainsLock) {
            final Map<String, Map<String, CacheEntry<DfsReferralDataInternal>>> domains = getTrustedDomains(tf);
            if (domains == null) {
                return false;
            }
            domain = domain.toLowerCase(Locale.ROOT);
            return domains.get(domain) != null;
        }
    }

        public LsarTrustInformation[] domains;
        /** Maximum count of domains. */
        public int max_count;

        @Override
        public void encode(NdrBuffer _dst) throws NdrException {
            _dst.align(4);
            _dst.enc_ndr_long(count);
            _dst.enc_ndr_referent(domains, 1);
            _dst.enc_ndr_long(max_count);

            if (domains != null) {

* **TCP doesn't know about "domains"**. Only about IP addresses.
    * The information about the **specific domain** requested goes in the **HTTP data**.
* The **HTTPS certificates** "certify" a **certain domain**, but the protocol and encryption happen at the TCP level, **before knowing** which domain is being dealt with.

    }

    @ParameterizedTest
    @MethodSource("domains")
    @DisplayName("getUserDomain handles null and empty")
    void getUserDomain_edges(String domain) {
        TestCredentials creds = new TestCredentials(domain, false, false, new Subject(), false);
        assertEquals(domain, creds.getUserDomain());
    }

    static Stream<String> domains() {
        return Stream.of(null, "", "SALES");
    }

* **TCP weiß nichts über „<abbr title="Domäne, Bereich, Wirkungsraum">Domains</abbr>“**. Nur über IP-Adressen.
    * Die Informationen über die angeforderte **spezifische Domain** befinden sich in den **HTTP-Daten**.
* Die **HTTPS-Zertifikate** „zertifizieren“ eine **bestimmte Domain**, aber das Protokoll und die Verschlüsselung erfolgen auf TCP-Ebene, **ohne zu wissen**, um welche Domain es sich handelt.

/**
 * A descriptor for a <i>discrete</i> {@code Comparable} domain such as all {@link Integer}
 * instances. A discrete domain is one that supports the three basic operations: {@link #next},
 * {@link #previous} and {@link #distance}, according to their specifications. The methods {@link
 * #minValue} and {@link #maxValue} should also be overridden for bounded types.
 *

/**
 * A descriptor for a <i>discrete</i> {@code Comparable} domain such as all {@link Integer}
 * instances. A discrete domain is one that supports the three basic operations: {@link #next},
 * {@link #previous} and {@link #distance}, according to their specifications. The methods {@link
 * #minValue} and {@link #maxValue} should also be overridden for bounded types.
 *