return (Iterator<T>) EmptyModifiableIterator.INSTANCE;
  }

  /** Returns an unmodifiable view of {@code iterator}. */
  public static <T extends @Nullable Object> UnmodifiableIterator<T> unmodifiableIterator(
      Iterator<? extends T> iterator) {
    checkNotNull(iterator);
    if (iterator instanceof UnmodifiableIterator) {

    @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

            return new PathSource(path.resolve(relative));
        }

        @Override
        public boolean equals(Object o) {
            return o == this || o instanceof PathSource that && Objects.equals(path, that.path);
        }

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

        @Override

                    org.eclipse.aether.artifact.Artifact artifact =
                            child.getDependency().getArtifact();
                    String message = artifact instanceof RelocatedArtifact relocated ? relocated.getMessage() : null;
                    logger.warn("The artifact " + child.getRelocations().get(0) + " has been relocated to " + artifact

    // methods that access the same node(s) repeatedly, such as Graphs.removeEdgesConnecting().
    this.nodeConnections =
        (nodeConnections instanceof TreeMap)
            ? new MapRetrievalCache<N, NetworkConnections<N, E>>(nodeConnections)
            : new MapIteratorCache<N, NetworkConnections<N, E>>(nodeConnections);

    // methods that access the same node(s) repeatedly, such as Graphs.removeEdgesConnecting().
    this.nodeConnections =
        (nodeConnections instanceof TreeMap)
            ? new MapRetrievalCache<N, NetworkConnections<N, E>>(nodeConnections)
            : new MapIteratorCache<N, NetworkConnections<N, E>>(nodeConnections);

            // The actual logic is tested in AbstractUpgradeGoalTest
            // Here we just verify that Check is properly configured as a subclass
            assertTrue(checkGoal instanceof AbstractUpgradeGoal, "Check should extend AbstractUpgradeGoal");
            assertFalse(checkGoal.shouldSaveModifications(), "Check should not save modifications unlike Apply goal");
        }
    }

                    return Optional.of(project.getArtifact().getFile().toPath());
                }
            }
        }
        Path path = paths.get(id);
        if (path == null && artifact instanceof DefaultArtifact defaultArtifact) {
            path = defaultArtifact.getArtifact().getPath();
        }
        return Optional.ofNullable(path);
    }

    @Override

  @Override
  public String toString() {
    return "Hashing.sipHash" + c + "" + d + "(" + k0 + ", " + k1 + ")";
  }

  @Override
  public boolean equals(@Nullable Object object) {
    if (object instanceof SipHashFunction) {
      SipHashFunction other = (SipHashFunction) object;
      return (c == other.c) && (d == other.d) && (k0 == other.k0) && (k1 == other.k1);
    }
    return false;
  }

  @Override

    }

    @Override
    protected String doBackward(String s) {
      return targetFormat.to(sourceFormat, s);
    }

    @Override
    public boolean equals(@Nullable Object obj) {
      if (obj instanceof StringConverter) {
        StringConverter that = (StringConverter) obj;
        return sourceFormat.equals(that.sourceFormat) && targetFormat.equals(that.targetFormat);
      }
      return false;
    }