protected int userInfoCacheSize = 10000;

    /** Queue for storing search logs. */
    protected Queue<SearchLog> searchLogQueue = new ConcurrentLinkedQueue<>();

    /** Queue for storing click logs. */
    protected Queue<ClickLog> clickLogQueue = new ConcurrentLinkedQueue<>();

    /** Cache for storing user information. */
    protected LoadingCache<String, UserInfo> userInfoCache;

    extends ForwardingMap<TypeToken<? extends @NonNull B>, B> implements TypeToInstanceMap<B> {
  /** Creates a new map. */
  public MutableTypeToInstanceMap() {}

  private final Map<TypeToken<? extends @NonNull B>, B> backingMap = new HashMap<>();

  @Override
  public <T extends @NonNull B> @Nullable T getInstance(Class<T> type) {
    return trustedGet(TypeToken.of(type));
  }

        if (listener == null) {
            return null;
        } else {
            return new TransferListenerAdapter(listener);
        }
    }

    private TransferListenerAdapter(ArtifactTransferListener listener) {
        this.listener = listener;
        this.artifacts = new IdentityHashMap<>();
        this.transfers = new IdentityHashMap<>();
    }

    @Override
    public void debug(String message) {}

    return new CollectionTestSuiteBuilder<E>().usingGenerator(generator);
  }

  @Override
  protected List<TestSuite> createDerivedSuites(
      FeatureSpecificTestSuiteBuilder<?, ? extends OneSizeTestContainerGenerator<Collection<E>, E>>
          parentBuilder) {
    List<TestSuite> derivedSuites = new ArrayList<>(super.createDerivedSuites(parentBuilder));

    return ofClassAndContents(Object.class, (E[]) new Object[0], asList(contents));
  }

  @SuppressWarnings("unchecked") // empty Object[] as E[]
  public static <E extends @Nullable Object> MinimalSet<E> from(Collection<? extends E> contents) {
    return ofClassAndContents(Object.class, (E[]) new Object[0], contents);
  }

     */

    TestListeningExecutorService e = new TestListeningExecutorService();

    TestRunnable runnable = new TestRunnable();
    ListenableFuture<?> runnableFuture = e.submit(runnable);
    assertThat(runnableFuture).isInstanceOf(TrustedListenableFutureTask.class);
    assertTrue(runnableFuture.isDone());
    assertTrue(runnable.run);

    ListenableFuture<String> callableFuture = e.submit(new TestCallable());

    return ofClassAndContents(Object.class, (E[]) new Object[0], asList(contents));
  }

  @SuppressWarnings("unchecked") // empty Object[] as E[]
  public static <E extends @Nullable Object> MinimalSet<E> from(Collection<? extends E> contents) {
    return ofClassAndContents(Object.class, (E[]) new Object[0], contents);
  }

     */

    TestListeningExecutorService e = new TestListeningExecutorService();

    TestRunnable runnable = new TestRunnable();
    ListenableFuture<?> runnableFuture = e.submit(runnable);
    assertThat(runnableFuture).isInstanceOf(TrustedListenableFutureTask.class);
    assertTrue(runnableFuture.isDone());
    assertTrue(runnable.run);

    ListenableFuture<String> callableFuture = e.submit(new TestCallable());

            // last resort; as ideally we should get ExitException only
            new SystemLogger(stdErr).error(e.getMessage(), e);
            return 1;
        } finally {
            if (classWorldManaged) {
                classWorld.close();
            }
        }
    }

    protected MessageBuilderFactory createMessageBuilderFactory() {
        return new JLineMessageBuilderFactory();
    }

      new ImmutableSortedMap<>(ImmutableSortedSet.emptySet(Ordering.natural()), ImmutableList.of());

  static <K, V> ImmutableSortedMap<K, V> emptyMap(Comparator<? super K> comparator) {
    if (Ordering.natural().equals(comparator)) {
      return of();
    } else {
      return new ImmutableSortedMap<>(ImmutableSortedSet.emptySet(comparator), ImmutableList.of());
    }