*
   * <p>A collection is considered immutable if:
   *
   * <ol>
   *   <li>All its mutation methods result in UnsupportedOperationException, and do not change the
   *       underlying contents.
   *   <li>All methods that return objects that can indirectly mutate the collection throw
   *       UnsupportedOperationException when those mutators are called.
   * </ol>
   *
   * @param collection the presumed-immutable collection

 * <ol>
 *   <li>Initialization: Sets up the crawler context and initializes the URL filter.</li>
 *   <li>Thread Creation: Creates a group of crawler threads to perform the actual crawling.</li>
 *   <li>Execution: Starts the crawler threads and waits for them to complete.</li>
 *   <li>Cleanup: Deletes the crawled data and clears the URL filter.</li>
 * </ol>
 *

     * Do not instantiate.
     */
    protected ClassLoaderUtil() {
    }

    /**
     * Returns the class loader.
     * <p>
     * The class loader is searched in the following order:
     * </p>
     * <ol>
     * <li>If the context class loader is set for the calling thread, that context class loader</li>
     * <li>If the class loader that loaded the target class can be obtained, that class loader</li>

/**
 * Implements the MD4 message digest algorithm in Java.
 * <p>
 * <b>References:</b>
 * <ol>
 *   <li> Ronald L. Rivest,
 *        "<a href="http://www.roxen.com/rfc/rfc1320.html">
 *        The MD4 Message-Digest Algorithm</a>",
 *        IETF RFC-1320 (informational).
 * </ol>
 *
 * <p><b>$Revision: 1.2 $</b>
 * @author  Raif S. Naffah
 */

 * {@link CrawlerContainer}, {@link LogHelper}, {@link CrawlerClientFactory}, and {@link CrawlerContext},
 * to perform its tasks.
 * </p>
 *
 * <p>
 * The crawling process involves the following steps:
 * </p>
 * <ol>
 *   <li>Fetching a URL from the queue using {@link UrlQueueService#poll(String)}.</li>
 *   <li>Checking if the URL is valid using {@link #isValid(UrlQueue)}.</li>

 * lookups.
 *
 * <p>During construction, names are normalized in two ways:
 *
 * <ol>
 *   <li>ASCII uppercase characters are converted to lowercase.
 *   <li>Unicode dot separators other than the ASCII period ({@code '.'}) are converted to the ASCII
 *       period.
 * </ol>
 *
 * <p>The normalized values will be returned from {@link #toString()} and {@link #parts()}, and will

m&a&rah?vk??f!.sg??h!.sg??i&e&h&dnort?rtsua?ssej??rkrejb??ksa??ol?t!.sg??u&dom?esum?r&ab?drejg?evle?os?uh?æb?øs??ttals???n&a&g&av?okssman?åv??jlis?or?r&g?rev???e&d&do&sen?ton??lah?r&agy&o?ø??ojfsam???g&iets?n&a&l&as?lab??n&avk?ævk??t&arg?ddosen??v&al?essov???i&d&ol?øl??l&ar?ær???yl??reb??iks?k&srot?y&or?ør???l&a&d&gnos?n&er?ojm?øjm??om??tloh??ug?åtloh??mmard?ojs&om?sendnas??ppolg?s&lahsladr&ojts?øjts??o??t&o&l?t-erts&ev?o?ø???roh?øl??vly&kkys?nav??yam-naj!.sg??øjs&om?sendnas???g&orf?ujb??i&dnaor...

 *     <li><code>alpha</code> or <code>a</code></li>
 *     <li><code>beta</code> or <code>b</code></li>
 *     <li><code>milestone</code> or <code>m</code></li>
 *     <li><code>rc</code> or <code>cr</code></li>
 *     <li><code>snapshot</code></li>
 *     <li><code>ga</code> or <code>final</code></li>
 *     <li><code>sp</code></li>
 *     </ol>

 * example round-trip using {@link com.google.common.primitives.Doubles#stringConverter}:
 *
 * <ol>
 *   <li>{@code stringConverter().convert("1.00")} returns the {@code Double} value {@code 1.0}
 *   <li>{@code stringConverter().reverse().convert(1.0)} returns the string {@code "1.0"} --
 *       <i>not</i> the same string ({@code "1.00"}) we started with
 * </ol>
 *
 * <p>Note that it should still be the case that the round-tripped and original objects are

 * <p>
 * The transformation process involves:
 * </p>
 * <ol>
 *   <li>Determining the character set encoding of the HTML content.</li>
 *   <li>Storing the HTML content as data in the {@link ResultData}.</li>
 *   <li>Extracting child URLs from the HTML content based on configured rules.</li>
 *   <li>Handling redirect URLs specified in the response headers.</li>
 * </ol>
 * <p>