public final class CrawlingParameterUtil {
    private static final ThreadLocal<UrlQueue<?>> URL_QUEUE_THREAD_LOCAL = new ThreadLocal<>();

    private static final ThreadLocal<CrawlerContext> ROBOT_CONTEXT_THREAD_LOCAL = new ThreadLocal<>();

    private static final ThreadLocal<UrlQueueService<UrlQueue<?>>> URL_QUEUE_SERVICE_THREAD_LOCAL = new ThreadLocal<>();

    return requireNonNull(DEST_TL.get());
  }

  /**
   * A thread-local destination buffer to keep us from creating new buffers. The starting size is
   * 1024 characters. If we grow past this we don't put it back in the threadlocal, we just keep
   * going and grow as needed.
   */
  private static final ThreadLocal<char[]> DEST_TL =
      new ThreadLocal<char[]>() {

    private final MavenExecutionResult result;

    private final RepositorySystemSession repositorySystemSession;

    private final Properties executionProperties;

    private ThreadLocal<MavenProject> currentProject = new ThreadLocal<>();

    /**
     * These projects have already been topologically sorted in the {@link org.apache.maven.Maven} component before

    private final ThreadLocal<Queue<Event>> queue =
        new ThreadLocal<Queue<Event>>() {
          @Override
          protected Queue<Event> initialValue() {
            return Queues.newArrayDeque();
          }
        };

    /** Per-thread dispatch state, used to avoid reentrant event dispatching. */
    private final ThreadLocal<Boolean> dispatching =
        new ThreadLocal<Boolean>() {

    protected RuleManager ruleManager;

    protected IntervalController intervalController;

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

    protected ThreadLocal<String[]> sitemapsLocal = new ThreadLocal<>();

    /** The number of a thread */
    protected int numOfThread = 10;

    protected int maxThreadCheckCount = 20;

    /** a max depth for crawling. -1 is no depth check. */

   *
   * <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

      }
    }
  }

  /**
   * ThreadLocal holding a single-slot int array holding hash code. Unlike the JDK8 version of this
   * class, we use a suboptimal int[] representation to avoid introducing a new type that can impede
   * class-unloading when ThreadLocals are not removed.
   */
  static final ThreadLocal<int @Nullable []> threadHashCode = new ThreadLocal<>();

  /** Generator of new random hash codes */

      };

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

    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");

      };

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