Pattern.compile("[A-Z0-9._%+-]+@[A-Z0-9.-]+\\.[A-Z]{2,6}", Pattern.CASE_INSENSITIVE);

    /**
     * Cache for storing resource file modification timestamps to enable cache busting.
     * The cache expires after 10 minutes and has a maximum size of 1000 entries.
     */
    private static LoadingCache<String, Long> resourceHashCache =