* In a package hierarchy, the {@linkplain #descriptors} map has either zero or one entry.
     * In a module hierarchy, the descriptors map may have an arbitrary number of entries,
     * including one (so the map size cannot be used as a criterion).
     *
     * @see #isModuleHierarchy()
     */
    private final boolean isModuleHierarchy;

    /**
     * Constructs an empty instance for non-modular dependencies.
     *

        Plugin plugin = Objects.requireNonNull(pluginDescriptor.getPlugin(), "pluginDescriptor.plugin cannot be null");

        Artifact pluginArtifact = Objects.requireNonNull(
                pluginDescriptor.getPluginArtifact(), "pluginDescriptor.pluginArtifact cannot be null");

        MavenProject project = session.getCurrentProject();

        final ClassRealm pluginRealm;

            return determineBuildOutputDirectoryForArtifact(project, artifact);
        }

        // The fall-through indicates that the artifact cannot be found;
        // for instance if package produced nothing or classifier problems.
        return null;
    }

    }

    private LegacyLocalRepositoryManager(ArtifactRepository delegate) {
        this.delegate = Objects.requireNonNull(delegate, "delegate cannot be null");

        ArtifactRepositoryLayout layout = delegate.getLayout();
        repo = new LocalRepository(
                new File(delegate.getBasedir()),

        return builder(nonNull(request, "request cannot be null"))
                .source(nonNull(source, "source cannot be null"))
                .build();
    }

    @Nonnull
    static ModelBuilderRequest build(@Nonnull Session session, @Nonnull ModelSource source) {
        return builder()
                .session(nonNull(session, "session cannot be null"))

    }

    public ClassRealm getCoreRealm() {
        return containerRealm;
    }

    public ClassRealm createProjectRealm(Model model, List<Artifact> artifacts) {
        Objects.requireNonNull(model, "model cannot be null");

        ClassLoader parent = getMavenApiRealm();

        return createRealm(getKey(model), RealmType.Project, parent, null, null, artifacts);
    }

    private static String getKey(Model model) {

            }

            @Override
            public List<ArtifactVersion> retrieveAvailableVersionsFromDeploymentRepository(
                    Artifact artifact, ArtifactRepository localRepository, ArtifactRepository remoteRepository) {
                throw new UnsupportedOperationException("Cannot get available versions in this test case");

                            // TODO add better exception that can detail the two conflicting artifacts
                            ArtifactResolutionException are = new ArtifactResolutionException(
                                    "Cannot resolve artifact version conflict between "
                                            + previous.getArtifact().getVersion() + " and "
                                            + node.getArtifact().getVersion(),

  It is more than simply understanding that m2 cannot go and check for the
  latest version of some snapshot artifact. If m2 is offline, SCM operations
  cannot succeed; no artifact downloads can take place, regardless of whether
  they are snapshot versions; artifact deployment cannot take place; certain
  types of tests cannot be setup, since the container used to run them cannot be
  reached or started.

        try {
            writer.write(sWriter, model.getDelegate());
        } catch (IOException | XMLStreamException e) {
            throw new ModelInterpolationException("Cannot serialize project model for interpolation.", e);
        }

        String serializedModel = sWriter.toString();
        serializedModel = interpolate(serializedModel, model, projectDir, config, debugEnabled);