Iterable<Integer> result = Iterables.concat(list1, list2, list3, list4, list5);
    assertEquals(asList(1, 4, 7, 8, 9, 10), newArrayList(result));
    assertEquals("[1, 4, 7, 8, 9, 10]", result.toString());
  }

  public void testConcatNullPointerException() {
    List<Integer> list1 = newArrayList(1);
    List<Integer> list2 = newArrayList(4);

    try {
      Iterables.concat(list1, null, list2);
      fail();

    }
    for (int run = 0; run < REPETITIONS; run++) {
      testItems();
      delegate.test();
    }
    return this;
  }

  private void testItems() {
    for (Object item : Iterables.concat(equalityGroups)) {
      assertTrue(item + " must not be Object#equals to null", !item.equals(null));
      assertTrue(
          item + " must not be Object#equals to an arbitrary object of another class",

          @Override
          public UnmodifiableIterator<EndpointPair<N>> iterator() {
            if (graph.isDirected()) {
              return Iterators.unmodifiableIterator(
                  Iterators.concat(
                      Iterators.transform(
                          graph.predecessors(node).iterator(),
                          (N predecessor) -> EndpointPair.ordered(predecessor, node)),

        }
        return getModelId() + " " + getLocation();
    }

    public static InputSource merge(InputSource src1, InputSource src2) {
        return new InputSource(Stream.concat(src1.sources(), src2.sources()).collect(Collectors.toSet()));
    }

    EntryTransformer<String, String, String> concat =
        new EntryTransformer<String, String, String>() {
          @Override
          public String transformEntry(String key, String value) {
            return key + value;
          }
        };
    Map<String, String> transformed = transformEntries(map, concat);

    assertEquals(ImmutableMap.of("a", "a4", "b", "b9"), transformed);

    EntryTransformer<String, String, String> concat =
        new EntryTransformer<String, String, String>() {
          @Override
          public String transformEntry(String key, String value) {
            return key + value;
          }
        };
    Map<String, String> transformed = transformEntries(map, concat);

    assertEquals(ImmutableMap.of("a", "a4", "b", "b9"), transformed);

    }

    static <T> Iterable<String> prepend(@NotBlank String first, Iterable<String> tail) {
      return Iterables.concat(ImmutableList.of(first), tail);
    }

    Iterable<String> prepend(Iterable<String> tail)
        throws IllegalArgumentException, NullPointerException {
      return Iterables.concat(Collections.nCopies(times, prefix), tail);
    }

import java.util.Map;

/** Benchmarks for memory consumption of map implementations. */
public class MapsMemoryBenchmark {
  static final Map<String, MapsImplEnum> mapEnums =
      uniqueIndex(
          Iterables.<MapsImplEnum>concat(
              Arrays.asList(MapImpl.values()),
              Arrays.asList(SortedMapImpl.values()),
              Arrays.asList(BiMapImpl.values())),
          toStringFunction());

  @Param({
    "HashMapImpl",

                boolean recursive) {
            List<Callable<InterimResult>> tasks = pomFiles.stream()
                    .map(pomFile -> ((Callable<InterimResult>)
                            () -> build(projectIndex, pomFile, concat(aggregatorFiles, pomFile), root, recursive)))
                    .collect(Collectors.toList());
            try {
                List<Future<InterimResult>> futures = executor.invokeAll(tasks);

     * Do not include the POM artifact as the file can't be set anyway.
     */
    private Stream<org.apache.maven.artifact.Artifact> getProjectArtifacts(MavenProject project) {
        return Stream.concat(Stream.of(project.getArtifact()), project.getAttachedArtifacts().stream());
    }

    private String id(org.apache.maven.artifact.Artifact artifact) {
        return artifact.getGroupId()