return this.cachedSubject;
        } catch (LoginException e) {
            log.error("Failed to create login context", e);
            // Cache null to ensure consistent behavior across calls
            this.cachedSubject = null;
            return null;
        }
    }

    /**
     * {@inheritDoc}
     *
     * @see jcifs.smb.SmbRenewableCredentials#renew()
     */
    @Override

    private SmbComBlankResponse blank_resp = null;
    private DfsReferral dfsReferral = null; // For getDfsPath() and getServerWithDfs()

    /**
     * DFS resolver instance
     */
    protected static Dfs dfs;

    NtlmPasswordAuthentication auth; // Cannot be null
    SmbTree tree = null; // Initially null
    String unc; // Initially null; set by getUncPath; never ends with '/'

     * @param resource the resource to track
     * @return resource ID for tracking
     */
    public String registerResource(AutoCloseable resource) {
        if (resource == null) {
            throw new IllegalArgumentException("Resource cannot be null");
        }

        String resourceId = generateResourceId(resource);
        ResourceHolder holder = new ResourceHolder(resourceId, resource, referenceQueue);

        UserCQ cq = new UserCQ();
        if (queryLambda != null) {
            queryLambda.callback(cq);
        }
        FilterAggregationBuilder builder = regFilterA(name, cq.getQuery());
        if (opLambda != null) {
            opLambda.callback(builder);
        }
        if (aggsLambda != null) {
            UserCA ca = new UserCA();
            aggsLambda.callback(ca);

        if (opLambda != null) {
            opLambda.callback(builder);
        }
    }

    public void setId_NotEqual(String id) {
        setId_NotTerm(id, null);
    }

    public void setId_NotTerm(String id) {
        setId_NotTerm(id, null);
    }

    public void setId_NotEqual(String id, ConditionOptionCall<BoolQueryBuilder> opLambda) {

     *
     * @param str the string to encode
     * @param encoding the character encoding to use
     * @return encoded byte array, or empty array if str is null
     */
    public static byte[] getBytes(final String str, final Charset encoding) {
        if (str == null) {
            return new byte[0];
        }
        return str.getBytes(encoding);
    }

    /**

        if (opLambda != null) {
            opLambda.callback(builder);
        }
    }

    public void setId_NotEqual(String id) {
        setId_NotTerm(id, null);
    }

    public void setId_NotTerm(String id) {
        setId_NotTerm(id, null);
    }

    public void setId_NotEqual(String id, ConditionOptionCall<BoolQueryBuilder> opLambda) {

        assertDoesNotThrow(() -> SingletonContext.init(null));
        assertNotNull(SingletonContext.getInstance()); // Should still initialize
    }

    @Test
    void testGetInstanceInitializesIfNull() {
        // Test getInstance initializes the context if it's null
        assertNull(getSingletonInstanceViaReflection()); // Ensure it's null initially
        CIFSContext context = SingletonContext.getInstance();

     *
     * @param model The POM to extract the plugin configuration from, may be {@code null}.
     * @param pluginGroupId The group id of the plugin whose configuration should be used, must not be {@code null} or
     *            empty.
     * @param pluginArtifactId The artifact id of the plugin whose configuration should be used, must not be
     *            {@code null} or empty.

        // Should write command byte + null terminator only
        assertEquals(2, used, "Null path should result in command byte + NUL");
        assertEquals(0x04, buffer[0] & 0xFF, "First byte must still be 0x04");
        assertEquals(0, buffer[1], "Second byte must be null terminator");
    }

    @Test
    @DisplayName("writeBytesWireFormat handles empty string gracefully")
    void testWriteEmptyString() {