// v1-->v2
        graph.addEdge(v1, v2, new MetadataGraphEdge("1.1", true, null, null, 2, 1));
        graph.addEdge(v1, v2, new MetadataGraphEdge("1.2", true, null, null, 2, 2));

        // v1-->v3
        graph.addEdge(v1, v3, new MetadataGraphEdge("1.1", true, null, null, 2, 1));
        graph.addEdge(v1, v3, new MetadataGraphEdge("1.2", true, null, null, 4, 2));

        // v3-->v4

    Preconditions.checkNotNull(task, "task must not be null!");
    Preconditions.checkNotNull(result, "result must not be null!");
    return delegate.submit(task, result);
  }

  @Override
  public ListenableFuture<?> submit(Runnable task) {
    Preconditions.checkNotNull(task, "task must not be null!");
    return delegate.submit(task);
  }

  @Override
  public <T> List<Future<T>> invokeAll(Collection<? extends Callable<T>> tasks)

        PersistedToolchains global = readToolchains(globalSource, request, problems);

        Source userSource = request.getUserToolchainsSource().orElse(null);
        PersistedToolchains user = readToolchains(userSource, request, problems);

        PersistedToolchains effective = toolchainsMerger.merge(user, global, false, null);

        if (hasErrors(problems)) {

      assertThat(e).hasMessageThat().isEqualTo("null [b, d]");
    }
  }

  public void testCheckArgument_nullArgs_failure() {
    try {
      Preconditions.checkArgument(false, "A %s C %s E", null, null);
      fail("no exception thrown");
    } catch (IllegalArgumentException e) {
      assertThat(e).hasMessageThat().isEqualTo("A null C null E");
    }
  }

  public void testCheckArgument_notEnoughArgs_failure() {

  private Set<DurationSpec> expireAfterAccesses = Sets.newHashSet((DurationSpec) null);
  private Set<DurationSpec> refreshes = Sets.newHashSet((DurationSpec) null);
  private Set<Strength> keyStrengths = Sets.newHashSet((Strength) null);
  private Set<Strength> valueStrengths = Sets.newHashSet((Strength) null);

  CacheBuilderFactory withConcurrencyLevels(Set<Integer> concurrencyLevels) {

        ClassRealm pluginRealm = pluginDescriptor.getClassRealm();

        if (pluginRealm == null) {
            try {
                setupPluginRealm(pluginDescriptor, session, null, null, null);
            } catch (PluginResolutionException e) {
                String msg = "Cannot setup plugin realm [mojoDescriptor=" + mojoDescriptor.getId()

import static com.google.common.collect.testing.features.MapFeature.ALLOWS_NULL_KEYS;
import static com.google.common.collect.testing.features.MapFeature.ALLOWS_NULL_KEY_QUERIES;
import static com.google.common.collect.testing.features.MapFeature.ALLOWS_NULL_VALUES;
import static com.google.common.collect.testing.features.MapFeature.ALLOWS_NULL_VALUE_QUERIES;
import static com.google.common.collect.testing.features.MapFeature.SUPPORTS_PUT;

          "remove(null) should return null or throw NullPointerException", getMap().remove(null));
    } catch (NullPointerException tolerated) {
    }
    expectUnchanged();
  }

  @MapFeature.Require({SUPPORTS_REMOVE, ALLOWS_NULL_KEY_QUERIES})
  public void testRemove_nullSupportedMissing() {
    assertNull("remove(null) should return null", getMap().remove(null));
    expectUnchanged();
  }

     * artifact files.
     *
     * @param session the {@link Session}, must not be {@code null}
     * @param root the Maven Dependency, must not be {@code null}
     * @return the collection result, never {@code null}
     * @throws DependencyCollectorException if the dependency tree could not be built
     * @throws IllegalArgumentException if an argument is null or invalid
     * @see #collect(DependencyCollectorRequest)
     */
    @Nonnull

    private final boolean lowerBoundInclusive;

    private final ArtifactVersion upperBound;

    private final boolean upperBoundInclusive;

    public static final Restriction EVERYTHING = new Restriction(null, false, null, false);

    public Restriction(
            ArtifactVersion lowerBound,
            boolean lowerBoundInclusive,
            ArtifactVersion upperBound,
            boolean upperBoundInclusive) {