public static <E> Set<Set<E>> combinations(Set<E> set, final int size) {
    final ImmutableMap<E, Integer> index = Maps.indexMap(set);
    checkNonnegative(size, "size");
    checkArgument(size <= index.size(), "size (%s) must be <= set.size() (%s)", size, index.size());
    if (size == 0) {
      return ImmutableSet.<Set<E>>of(ImmutableSet.<E>of());
    } else if (size == index.size()) {
      return ImmutableSet.<Set<E>>of(index.keySet());

        List<Path> unresolved = dispatched.get(PathType.UNRESOLVED);
        assertEquals(3, dispatched.size());
        assertEquals(1, unresolved.size());
        assertEquals(8, classes.size()); // "plexus.pom" and "junit.jar" are excluded.
        assertEquals(1, modules.size());
        assertEquals("plexus-1.0.11.pom", unresolved.get(0).getFileName().toString());

        Map map = project1.getArtifactMap();
        assertNotNull(map, "No artifacts");
        assertTrue(map.size() > 0, "No Artifacts");
        assertTrue(map.size() == 3, "Set size should be 3, is " + map.size());

        Artifact a = (Artifact) map.get("maven-test:t10-a");
        Artifact b = (Artifact) map.get("maven-test:t10-b");

        assertNotNull(res, "null classpath container after compile transform");
        assertNotNull(res.getClasspath(), "null classpath after compile transform");
        assertEquals(3, res.getClasspath().size(), "compile classpath should have 3 entries");
    }

    // ------------------------------------------------------------------------------------------
    @Test
    void testRuntimeClasspathTransform() throws Exception {

     */
    @Override
    public ImmutableBiMap<K, V> buildOrThrow() {
      if (size == 0) {
        return of();
      }
      if (valueComparator != null) {
        if (entriesUsed) {
          alternatingKeysAndValues = Arrays.copyOf(alternatingKeysAndValues, 2 * size);
        }
        sortEntries(alternatingKeysAndValues, size, valueComparator);
      }
      entriesUsed = true;

     * added.
     *
     * @throws IllegalArgumentException if duplicate key pairs were added
     * @since 31.0
     */
    public ImmutableTable<R, C, V> buildOrThrow() {
      int size = cells.size();
      switch (size) {
        case 0:
          return of();
        case 1:
          return new SingletonImmutableTable<>(Iterables.getOnlyElement(cells));
        default:

    if (generate != null) {
      ImmutableList<Parameter> params = Invokable.from(generate).getParameters();
      List<Object> args = Lists.newArrayListWithCapacity(params.size());
      TypeVariable<?>[] typeVars = rawType.getTypeParameters();
      for (int i = 0; i < params.size(); i++) {
        TypeToken<?> paramType = type.resolveType(typeVars[i]);
        // We require all @Generates methods to either be parameter-less or accept non-null

        }
    }

    private Model assembleInheritance(
            List<Model> lineage, ModelBuilderRequest request, ModelProblemCollector problems) {
        Model parent = lineage.get(lineage.size() - 1);
        for (int i = lineage.size() - 2; i >= 0; i--) {
            Model child = lineage.get(i);
            parent = inheritanceAssembler.assembleModelInheritance(child, parent, request, problems);
        }
        return parent;

    }

    private List<Artifact> toMavenArtifacts(DependencyResult dependencyResult) {
        List<Artifact> artifacts =
                new ArrayList<>(dependencyResult.getArtifactResults().size());
        dependencyResult.getArtifactResults().stream()
                .filter(ArtifactResult::isResolved)
                .forEach(a -> artifacts.add(RepositoryUtils.toArtifact(a.getArtifact())));

      boolean timed,
      long timeout,
      TimeUnit unit)
      throws InterruptedException, ExecutionException, TimeoutException {
    checkNotNull(executorService);
    checkNotNull(unit);
    int ntasks = tasks.size();
    checkArgument(ntasks > 0);
    List<Future<T>> futures = Lists.newArrayListWithCapacity(ntasks);
    BlockingQueue<Future<T>> futureQueue = Queues.newLinkedBlockingQueue();
    long timeoutNanos = unit.toNanos(timeout);