* We use `fromNullable` instead of `of` because `WeakReference.get()` has a nullable return
     * type.
     *
     * In practice, we are very unlikely to see `null`: The `WeakReference` to the enum constant
     * won't be cleared as long as the enum constant is referenced somewhere, and the enum constant
     * is referenced somewhere for as long as the enum class is loaded. *Maybe in theory* the enum

     *       ThreadConfinedTaskQueue object must be created for each inline execution, because
     *       observing a null thread does not mean the object is safe to reuse.
     *   <li>If this field's value is some other thread object, we know that it's not our thread.
     *   <li>If this field's value == null because it originally belonged to another thread and that
     *       thread cleared it, we still know that it's not associated with our thread

            synchronized (result.lock) {
              assertEquals(
                  "The test should have cleared the stack (say, by virtue of running runTearDown)",
                  0,
                  result.stack.size());
            }
          }
        });
    return result;
  }

  private static final class ThrowingTearDown implements TearDown {

    private final String id;

       * pass.
       *
       * 2. We would probably choose to compare exceptions using == instead of equals() (for
       * consistency with how weak references are cleared). That's a behavior change -- arguably the
       * removal of a feature.
       *
       * Fortunately, exceptions rarely contain references to expensive resources.
       */

      //

    }

    public void test_clearCache() {
        // Test that clearCache doesn't throw exception
        popularWordHelper.clearCache();

        // Verify cache is cleared (we can't directly test this without accessing the cache)
        // But we can test that it doesn't throw exceptions
        assertTrue(true);
    }

    public void test_init_configuration() {

    assertEquals(1, segment.count);
    assertSame(newValue, segment.get(key, hash));

    // cleared
    entry.setValueReference(oldValueRef);
    assertSame(oldValue, segment.get(key, hash));
    oldValueRef.clear();
    assertFalse(segment.replace(key, hash, oldValue, newValue));
    assertEquals(0, segment.count);
    assertNull(segment.get(key, hash));
  }

   * clear()} clears all table mappings.
   */
  @WeakOuter
  private abstract class TableSet<T> extends ImprovedAbstractSet<T> {
    @Override
    public boolean isEmpty() {
      return backingMap.isEmpty();
    }

    @Override
    public void clear() {
      backingMap.clear();
    }
  }

  /**
   * {@inheritDoc}
   *

     *
     * @param form the search form
     * @return HTML response for the duplicate host list page with cleared search
     */
    @Execute
    @Secured({ ROLE, ROLE + VIEW })
    public HtmlResponse reset(final SearchForm form) {
        duplicateHostPager.clear();
        return asHtml(path_AdminDuplicatehost_AdminDuplicatehostJsp).renderWith(data -> {
            searchPaging(data, form);

        crawlingInfoHelper.putToInfoMap("error_count", "5");

        // Store with create=true
        crawlingInfoHelper.store(sessionId, true);

        // Verify infoMap is cleared
        assertNull(crawlingInfoHelper.infoMap);
    }

    public void test_store_existing() {
        final String sessionId = "existing-session";
        final CrawlingInfo existingInfo = new CrawlingInfo();

     *
     * @param form the search form to reset
     * @return HTML response for the failure URL list page with cleared search
     */
    @Execute
    @Secured({ ROLE, ROLE + VIEW })
    public HtmlResponse reset(final SearchForm form) {
        failureUrlPager.clear();
        return asHtml(path_AdminFailureurl_AdminFailureurlJsp).renderWith(data -> {
            searchPaging(data, form);
        });