/** Constant for Kryo serializer type. */
    protected static final String KRYO = "kryo";

    /** ThreadLocal container for Kryo instances to ensure thread safety. */
    protected final ThreadLocal<Kryo> kryoThreadLocal;

    /**
     * Constructs a new DataSerializer.
     * <p>
     * Initializes the ThreadLocal Kryo instances with appropriate configuration.

    /** Per-thread queue of events to dispatch. */
    @SuppressWarnings("ThreadLocalUsage") // Each Dispatcher needs its own state.
    private final ThreadLocal<Queue<Event>> queue =
        new ThreadLocal<Queue<Event>>() {
          @Override
          protected Queue<Event> initialValue() {
            return new ArrayDeque<>();
          }
        };

        public void run() {}
      };

  public void testDirectExecutorServiceServiceInThreadExecution() throws Exception {
    ListeningExecutorService executor = newDirectExecutorService();
    ThreadLocal<Integer> threadLocalCount =
        new ThreadLocal<Integer>() {
          @Override
          protected Integer initialValue() {
            return 0;
          }
        };

     */
    protected Set<String> robotsTxtUrlSet = new LruHashSet<>(10000);

    /**
     * Thread-local storage for sitemaps.
     */
    protected ThreadLocal<String[]> sitemapsLocal = new ThreadLocal<>();

    /** The number of threads used by the crawler */
    protected int numOfThread = 10;

    /** The maximum number of times to check for active threads. */

  }

  private abstract static class FileFactory {

    private static final Logger logger = Logger.getLogger(FileFactory.class.getName());

    private final ThreadLocal<File> fileThreadLocal = new ThreadLocal<>();

    File createFile() throws IOException {
      File file = File.createTempFile("SinkSourceFile", "txt");
      fileThreadLocal.set(file);
      return file;
    }

   *
   * <p>This class would certainly be simpler and easier to reason about if it were built with
   * ThreadLocal; however, ThreadLocal is not well optimized for the case where the ThreadLocal is
   * non-static, and is initialized/removed frequently - this causes churn in the Thread specific
   * hashmaps. Using a static ThreadLocal to avoid that overhead would mean that different

    protected Map<String, String> metadataXpathMap = new HashMap<>();

    /** Thread-local instance of XPathAPI for thread-safe XPath evaluation. */
    private final ThreadLocal<XPathAPI> xpathAPI = new ThreadLocal<>();

    /**
     * Creates a new HtmlExtractor instance.
     */
    public HtmlExtractor() {
        super();
    }

    @Override

    }

    /** Monitor interval in seconds (default: 1 hour) */
    protected int monitorInterval = 60 * 60;// 1hour

    /** Thread-local storage for job runtime information */
    protected ThreadLocal<LaJobRuntime> jobRuntimeLocal = new ThreadLocal<>();

    /**
     * Registers a scheduled job with the job manager.
     *
     * @param scheduledJob the scheduled job to register
     */

    private static final Logger logger = LogManager.getLogger(CrawlerStatsHelperTest.class);

    private CrawlerStatsHelper crawlerStatsHelper;

    private ThreadLocal<String> localLogMsg = new ThreadLocal<>();

    @Override
    public void setUp() throws Exception {
        super.setUp();
        ComponentUtil.register(new SystemHelper(), "systemHelper");

   */
  // This is logically a Set, but an ArrayList is used to minimize the amount
  // of allocation done on lock()/unlock().
  private static final ThreadLocal<ArrayList<LockGraphNode>> acquiredLocks =
      new ThreadLocal<ArrayList<LockGraphNode>>() {
        @Override
        protected ArrayList<LockGraphNode> initialValue() {
          return Lists.<LockGraphNode>newArrayListWithCapacity(3);
        }