private static final Oid JGSS_KRB5_NAME_OID;
    private static final Oid JGSS_KRB5_MECH_OID;

    static {
        KRB5_MECH_OID = new ASN1ObjectIdentifier("1.2.840.113554.1.2.2");
        KRB5_MS_MECH_OID = new ASN1ObjectIdentifier("1.2.840.48018.1.2.2");
        SUPPORTED_MECHS = new ASN1ObjectIdentifier[] { KRB5_MECH_OID, KRB5_MS_MECH_OID };

        Oid krbNameOid = null;
        Oid krbMechOid = null;

    @ParameterizedTest
    @MethodSource("supportedMechs")
    @DisplayName("isSupported returns true for supported OIDs")
    void isSupported_supportedOids(ASN1ObjectIdentifier oid) {
        assertTrue(ctx.isSupported(oid));
        assertTrue(ctx.isPreferredMech(oid));
    }

    @Test
    @DisplayName("isSupported returns false for null/unknown OIDs")
    void isSupported_unknownOrNull() {

    @MethodSource("preferredMechData_nonAnonymous")
    void isPreferredMech_nonAnonymous(ASN1ObjectIdentifier oid, boolean expected) {
        Kerb5Authenticator auth = new Kerb5Authenticator(new Subject());
        assertEquals(expected, auth.isPreferredMech(oid));
    }

    static Object[][] preferredMechData_anonymous() {

    static {
        try {
            SPNEGO_MECH_OID = new ASN1ObjectIdentifier("1.3.6.1.5.5.2");
        } catch (final IllegalArgumentException e) {
            log.error("Failed to initialize OID", e);
        }
    }

    private final SSPContext mechContext;

    private boolean firstResponse = true;
    private boolean completed;

    private ASN1ObjectIdentifier[] mechs;

    /**
     * The NTLMSSP OID (1.3.6.1.4.1.311.2.2.10) used in SPNEGO negotiation.
     */
    public static ASN1ObjectIdentifier NTLMSSP_OID;

    static {
        try {
            NTLMSSP_OID = new ASN1ObjectIdentifier("1.3.6.1.4.1.311.2.2.10");
        } catch (final IllegalArgumentException e) {
            log.error("Failed to parse OID", e);
        }
    }

            final ASN1ObjectIdentifier spnego = (ASN1ObjectIdentifier) vec.getObjectAt(0);
            if (!SPNEGO_OID.equals(spnego)) {
                throw new IOException("Malformed SPNEGO token, OID " + spnego);
            }
            ASN1TaggedObject tagged = (ASN1TaggedObject) vec.getObjectAt(1);
            if (tagged.getTagNo() != 0) {