String CRAWLER_METADATA_CONTENT_EXCLUDES = "crawlerMetadataContentExcludes";

    Map<String, Object> propMap = new ConcurrentHashMap<>();

    String getOrDefault(String propertyKey, String defaultValue);

    //
    // system.properties
    //

    default void storeSystemProperties() {
        ComponentUtil.getSystemProperties().store();
    }

     * @param propertyKey The key of the property. (NotNull)
     * @return The value of found property. (NotNull: if not found, exception)
     * @throws ConfigPropertyNotFoundException When the property is not found.
     */
    String get(String propertyKey);

    /**
     * Is the property true?
     * @param propertyKey The key of the property which is boolean type. (NotNull)