labelQueue.add(label);
    }

    /**
     * Dispatches all listeners {@linkplain #enqueue enqueued} prior to this call, serially and in
     * order.
     */
    @SuppressWarnings("CatchingUnchecked") // sneaky checked exception
    void dispatch() {
      boolean scheduleEventRunner = false;
      synchronized (this) {
        if (!isThreadScheduled) {
          isThreadScheduled = true;

   *     remove()}, {@code set()}, and {@code add()} calls
   */
  protected void verify(List<E> elements) {}

  /** Executes the test. */
  @SuppressWarnings("CatchingUnchecked") // sneaky checked exception
  public final void test() {
    try {
      recurse(0);
    } catch (Exception e) { // sneaky checked exception
      throw new RuntimeException(Arrays.toString(stimuli), e);

     * parameter, or if the constructor or factory method throws exception.
     *
     * @return this tester
     */
    @CanIgnoreReturnValue
    @SuppressWarnings("CatchingUnchecked") // sneaky checked exception
    public FactoryMethodReturnValueTester testSerializable() throws Exception {
      for (Invokable<?, ?> factory : getFactoriesToTest()) {
        Object instance = instantiate(factory);

    private final Adder adder;

    FailsToPropagateException(Adder adder) {
      this.adder = adder;
    }

    @Override
    @SuppressWarnings("CatchingUnchecked") // sneaky checked exception
    public int add(int a, int b) {
      try {
        return adder.add(a, b);
      } catch (Exception e) { // sneaky checked exception
        // swallow!
        return 0;

   *     remove()}, {@code set()}, and {@code add()} calls
   */
  protected void verify(List<E> elements) {}

  /** Executes the test. */
  @SuppressWarnings("CatchingUnchecked") // sneaky checked exception
  public final void test() {
    try {
      recurse(0);
    } catch (Exception e) { // sneaky checked exception
      throw new RuntimeException(Arrays.toString(stimuli), e);

    private final Adder adder;

    FailsToPropagateException(Adder adder) {
      this.adder = adder;
    }

    @Override
    @SuppressWarnings("CatchingUnchecked") // sneaky checked exception
    public int add(int a, int b) {
      try {
        return adder.add(a, b);
      } catch (Exception e) { // sneaky checked exception
        // swallow!
        return 0;

     * parameter, or if the constructor or factory method throws exception.
     *
     * @return this tester
     */
    @CanIgnoreReturnValue
    @SuppressWarnings("CatchingUnchecked") // sneaky checked exception
    public FactoryMethodReturnValueTester testSerializable() throws Exception {
      for (Invokable<?, ?> factory : getFactoriesToTest()) {
        Object instance = instantiate(factory);

  public final void setAccessible(boolean flag) {
    accessibleObject.setAccessible(flag);
  }

  /** See {@link java.lang.reflect.AccessibleObject#trySetAccessible()}. */
  @SuppressWarnings("CatchingUnchecked") // sneaky checked exception
  public final boolean trySetAccessible() {
    // We can't call accessibleObject.trySetAccessible since that was added in Java 9 and this code

        builder.append(lenientToString(args[i]));
        prefix = ", ";
      }
      builder.append(']');
    }

    return builder.toString();
  }

  @SuppressWarnings("CatchingUnchecked") // sneaky checked exception
  private static String lenientToString(@Nullable Object o) {
    if (o == null) {
      return "null";
    }
    try {
      return o.toString();

  protected Map<K, V> makeEitherMap() {
    try {
      return makePopulatedMap();
    } catch (UnsupportedOperationException e) {
      return makeEmptyMap();
    }
  }

  @SuppressWarnings("CatchingUnchecked") // sneaky checked exception
  protected final boolean supportsValuesHashCode(Map<K, V> map) {
    // get the first non-null value
    Collection<V> values = map.values();
    for (V value : values) {