public @Nullable E pollLast() {
      synchronized (mutex) {
        return delegate().pollLast();
      }
    }

    @Override
    public E getFirst() {
      synchronized (mutex) {
        return delegate().getFirst();
      }
    }

    @Override
    public E getLast() {
      synchronized (mutex) {
        return delegate().getLast();
      }
    }

    public @Nullable E pollLast() {
      synchronized (mutex) {
        return delegate().pollLast();
      }
    }

    @Override
    public E getFirst() {
      synchronized (mutex) {
        return delegate().getFirst();
      }
    }

    @Override
    public E getLast() {
      synchronized (mutex) {
        return delegate().getLast();
      }
    }

                List<RequestData> requestDataList = new ArrayList<>();
                for (final String childUrl : getUrlFromTagAttribute(baseUri, document, entry.getFirst(), entry.getSecond(),
                        responseData.getCharSet())) {
                    requestDataList.add(RequestDataBuilder.newRequestData().get().url(childUrl).build());
                }

        }
    }

    @Override
    protected void writeHeaders(final HttpServletResponse response) {
        ComponentUtil.getFessConfig().getApiJsonResponseHeaderList().forEach(e -> response.setHeader(e.getFirst(), e.getSecond()));
    }

    /**
     * Writes a JSON response.
     * @param status The status code.
     * @param t The throwable.
     */

   *
   * @throws NullPointerException if the first element is null; if this is a possibility, use {@code
   *     iterator().next()} or {@link Iterables#getFirst} instead.
   */
  @SuppressWarnings("nullness") // Unsafe, but we can't do much about it now.
  public final Optional<@NonNull E> first() {
    Iterator<E> iterator = getDelegate().iterator();

    }

    <T> void clearReferenceQueue(ReferenceQueue<T> referenceQueue) {
      while (referenceQueue.poll() != null) {}
    }

    /** Returns first entry of bin for given hash. */
    @Nullable E getFirst(int hash) {
      // read this volatile field only once
      AtomicReferenceArray<E> table = this.table;
      return table.get(hash & (table.length() - 1));
    }

                            closeableHttpClient.getClass().getName());
                }
            }
        }

        formSchemeList.forEach(p -> {
            final FormScheme scheme = p.getFirst();
            final Credentials credentials = p.getSecond();
            scheme.authenticate(credentials, (request, consumer) -> {

                // request header

    }
  }

  /**
   * Returns the next element in {@code iterator} or {@code defaultValue} if the iterator is empty.
   * The {@link Iterables} analog to this method is {@link Iterables#getFirst}.
   *
   * @param defaultValue the default value to return if the iterator is empty
   * @return the next element of {@code iterator} or the default value
   * @since 7.0
   */
  @ParametricNullness

        if (weight > 0) {
          return e;
        }
      }
      throw new AssertionError();
    }

    /** Returns first entry of bin for given hash. */
    ReferenceEntry<K, V> getFirst(int hash) {
      // read this volatile field only once
      AtomicReferenceArray<ReferenceEntry<K, V>> table = this.table;
      return table.get(hash & (table.length() - 1));
    }

   */
  public void testAddAtIndex_unsupportedPresent() {
    assertThrows(UnsupportedOperationException.class, () -> getList().add(0, e0()));
    expectUnchanged();
  }

  @ListFeature.Require(SUPPORTS_ADD_WITH_INDEX)
  public void testAddAtIndex_supportedNotPresent() {
    getList().add(0, e3());
    expectAdded(0, e3());
  }

  @CollectionFeature.Require(FAILS_FAST_ON_CONCURRENT_MODIFICATION)