checkNotNull(values);
    // make sure we only call values.iterator() once
    // and we only call get(key) if values is nonempty
    if (values instanceof Collection) {
      Collection<? extends V> valueCollection = (Collection<? extends V>) values;
      return !valueCollection.isEmpty() && get(key).addAll(valueCollection);
    } else {

         */
        for (Iterator<? extends Metadata> it = metadatas.iterator(); it.hasNext(); ) {
            Metadata metadata = it.next();
            if (metadata instanceof PluginsMetadata) {
                it.remove();
                PluginsMetadata pluginMetadata = (PluginsMetadata) metadata;
                processedPlugins.put(pluginMetadata.getGroupId(), pluginMetadata);
            }

                mavenRepositorySystem,
                lookup,
                runtimeInformation);
    }

    public ArtifactRepository toArtifactRepository(RemoteRepository repository) {
        if (repository instanceof DefaultRemoteRepository) {
            org.eclipse.aether.repository.RemoteRepository rr = ((DefaultRemoteRepository) repository).getRepository();

            try {

   * returned {@code CharSource} and any {@code Reader} instances created by it is unspecified if
   * the {@code charSequence} is mutated while it is being read, so don't do that.
   *
   * @since 15.0 (since 14.0 as {@code CharStreams.asCharSource(String)})
   */
  public static CharSource wrap(CharSequence charSequence) {
    return charSequence instanceof String
        ? new StringCharSource((String) charSequence)

   *
   * @since 13.0
   * @since 4.0 (in Equivalences)
   */
  public static Equivalence<Object> identity() {
    return Identity.INSTANCE;
  }

  static final class Equals extends Equivalence<Object> implements Serializable {

    static final Equals INSTANCE = new Equals();

    @Override
    protected boolean doEquivalent(Object a, Object b) {
      return a.equals(b);
    }

    @Override

    @Override
    public V getValue() {
      return value;
    }

    @Override
    public boolean equals(@Nullable Object object) {
      // Cannot use key and value equivalence
      if (object instanceof Entry) {
        Entry<?, ?> that = (Entry<?, ?>) object;
        return key.equals(that.getKey()) && value.equals(that.getValue());
      }
      return false;
    }

    @Override

    final int hash;

    Element(int hash) {
      this.hash = hash;
    }

    @Override
    public boolean equals(@Nullable Object obj) {
      return this == obj || (obj instanceof Element && ((Element) obj).hash == hash);
    }

    @Override
    public int hashCode() {
      return hash;
    }

    @Override
    public int compareTo(Element that) {

    /**
     * used to eliminate exact duplicates in the edge list
     */
    @Override
    @SuppressWarnings("checkstyle:equalshashcode")
    public boolean equals(Object o) {
        if (o instanceof MetadataGraphEdge) {
            MetadataGraphEdge e = (MetadataGraphEdge) o;

            return objectsEqual(version, e.version)
                    && ArtifactScopeEnum.checkScope(scope)

  }

  @Override
  public final boolean equals(@CheckForNull Object obj) {
    if (obj == this) {
      return true;
    }
    if (!(obj instanceof ValueGraph)) {
      return false;
    }
    ValueGraph<?, ?> other = (ValueGraph<?, ?>) obj;

    return isDirected() == other.isDirected()
        && nodes().equals(other.nodes())

  abstract ImmutableMap<K, V> map();

  @Override
  public int size() {
    return map().size();
  }

  @Override
  public boolean contains(@CheckForNull Object object) {
    if (object instanceof Entry) {
      Entry<?, ?> entry = (Entry<?, ?>) object;
      V value = map().get(entry.getKey());
      return value != null && value.equals(entry.getValue());
    }
    return false;
  }

  @Override