throw new CrawlerSystemException("key or value is null.");
        }

        featureMap.put(key, value);
    }

    /**
     * Adds a parser property configuration.
     *
     * @param key the property key
     * @param value the property value
     * @throws CrawlerSystemException if key or value is null
     */
    public void addProperty(final String key, final String value) {

        }

        featureMap.put(key, value);
    }

    /**
     * Adds a property to the extractor.
     *
     * @param key   the key of the property
     * @param value the value of the property
     */
    public void addProperty(final String key, final String value) {
        if (StringUtil.isBlank(key) || StringUtil.isBlank(value)) {

    /** Property key for SMB authentications configuration. */
    public static final String SMB_AUTHENTICATIONS_PROPERTY = "smbAuthentications";

    /** Property key for SMB allowed SID entries. */
    public static final String SMB_ALLOWED_SID_ENTRIES = "smbAllowedSidEntries";

    /** Property key for SMB denied SID entries. */

    /** Property key for SMB1 authentications configuration. */
    public static final String SMB_AUTHENTICATIONS_PROPERTY = "smb1Authentications";

    /** Property key for SMB1 access control entries. */
    public static final String SMB_ACCESS_CONTROL_ENTRIES = "smb1AccessControlEntries";

    /** Property key for SMB1 allowed SID entries. */

            fail("Should throw exception with null container");
        } catch (NullPointerException e) {
            // Expected
        }
    }

    /**
     * Test concurrent property access
     */
    public void test_concurrentPropertyAccess() throws Exception {
        final int threadCount = 10;
        final int iterationsPerThread = 100;

            parser.setProperty(XMLConstants.ACCESS_EXTERNAL_SCHEMA, StringUtil.EMPTY);
        } catch (final Exception e) {
            if (logger.isDebugEnabled()) {
                logger.debug("Failed to set a property.", e);
            }
        }
    }

    /**
     * SAX handler for parsing XML sitemaps.
     */
    protected static class XmlSitemapsHandler extends DefaultHandler {

    public static final String FTP_FILE_GROUP = "ftpFileGroup";

    /** Metadata key for FTP file user */
    public static final String FTP_FILE_USER = "ftpFileUser";

    /** Property name for FTP authentications */
    public static final String FTP_AUTHENTICATIONS_PROPERTY = "ftpAuthentications";

    /**
     * Constructs a new FtpClient.
     */
    public FtpClient() {

 * and handling the overall crawling lifecycle.
 *
 * <p>It implements the Runnable interface to be executed in a separate thread,
 * and the AutoCloseable interface to ensure resources are properly released after use.
 *
 * <p>The crawler uses several services and components, such as UrlQueueService, DataService,
 * UrlFilter, RuleManager, CrawlerContainer, IntervalController, and CrawlerClientFactory,