ThreadFactory threadFactory = mock(ThreadFactory.class);
    when(executor.getThreadFactory()).thenReturn(threadFactory);
    application.getExitingExecutorService(executor).execute(EMPTY_RUNNABLE);
    verify(executor).execute(EMPTY_RUNNABLE);
  }

  @AndroidIncompatible // Mocking ExecutorService is forbidden there. TODO(b/218700094): Don't mock.

  }

  public void testEmptiesFirst() {
    Optional<String> empty = Optional.empty();
    Optional<String> abc = Optional.of("abc");
    Optional<String> z = Optional.of("z");

    Comparator<Optional<String>> comparator = Comparators.emptiesFirst(comparing(String::length));
    Helpers.testComparator(comparator, empty, z, abc);

    // Just demonstrate that no explicit type parameter is required

   * @param elements the elements that the multiset should contain
   * @throws IllegalArgumentException if {@code elements} is empty
   */
  public static <E extends Enum<E>> EnumMultiset<E> create(Iterable<E> elements) {
    Iterator<E> iterator = elements.iterator();
    checkArgument(iterator.hasNext(), "EnumMultiset constructor passed empty Iterable");
    EnumMultiset<E> multiset = new EnumMultiset<>(iterator.next().getDeclaringClass());

    StringSubscriber s2 = new StringSubscriber();
    ObjectSubscriber o1 = new ObjectSubscriber();

    Iterator<Subscriber> empty = registry.getSubscribers("");
    assertFalse(empty.hasNext());

    empty = registry.getSubscribers("");

    registry.register(s1);
    assertFalse(empty.hasNext());

    Iterator<Subscriber> one = registry.getSubscribers("");
    assertEquals(s1, one.next().target);

}

// Use a Scanner with a custom split function to parse a comma-separated
// list with an empty final value.
func ExampleScanner_emptyFinalToken() {
	// Comma-separated list; last entry is empty.
	const input = "1,2,3,4,"
	scanner := bufio.NewScanner(strings.NewReader(input))
	// Define a split function that separates on commas.

        if (!result.hasExceptions()) {
            return Optional.empty();
        }

        List<MavenProject> sortedProjects = result.getTopologicallySortedProjects();

        boolean hasNoSuccess =
                sortedProjects.stream().noneMatch(project -> result.getBuildSummary(project) instanceof BuildSuccess);

        if (hasNoSuccess) {
            return Optional.empty();
        }

      assertThat(expected.message).isEqualTo("Code 1005 is reserved and may not be used.")
    }
  }

  @Test fun serverEmptyPing() {
    serverWriter.writePing(EMPTY)
    assertData("8900")
  }

  @Test fun clientEmptyPing() {
    clientWriter.writePing(EMPTY)
    assertData("898060b420bb")
  }

  @Test fun serverPingWithPayload() {
    serverWriter.writePing("Hello".encodeUtf8())
    assertData("890548656c6c6f")

  }

  @SuppressWarnings("DoNotCall")
  public void testEmpty() {
    Iterator<Object> empty = new EmptyAbstractSequentialIterator<>();
    assertFalse(empty.hasNext());
    try {
      empty.next();
      fail();
    } catch (NoSuchElementException expected) {
    }
    try {
      empty.remove();
      fail();
    } catch (UnsupportedOperationException expected) {
    }
  }

    /**
     * Gets the current project (if any).
     *
     * @return the current project or {@code empty()} if not applicable
     */
    @Nonnull
    Optional<Project> getProject();

    /**
     * Gets the current mojo execution (if any).
     *
     * @return the current mojo execution or {@code empty()} if not applicable
     */
    @Nonnull
    Optional<MojoExecution> getMojoExecution();

    /**

                  protected Set<String> create(String[] elements) {
                    return Sets.union(Sets.<String>newHashSet(), Sets.<String>newHashSet());
                  }
                })
            .named("empty U empty")
            .withFeatures(
                CollectionSize.ZERO, CollectionFeature.NONE, CollectionFeature.ALLOWS_NULL_VALUES)
            .createTestSuite());

    suite.addTest(
        SetTestSuiteBuilder.using(