if (proxy != null) {
                org.apache.maven.repository.Proxy p = new org.apache.maven.repository.Proxy();
                p.setHost(proxy.getHost());
                p.setProtocol(proxy.getType());
                p.setPort(proxy.getPort());
                if (proxy.getAuthentication() != null) {
                    repo = new RemoteRepository.Builder(repo).setProxy(proxy).build();

                public List<Exception> getExceptions() {
                    return result.getExceptions();
                }

                @Override
                public Node getRoot() {
                    return session.getNode(result.getRoot(), request.getVerbose());
                }
            };
        } catch (DependencyCollectionException e) {

                public List<Exception> getExceptions() {
                    return result.getExceptions();
                }

                @Override
                public Node getRoot() {
                    return session.getNode(result.getRoot(), request.getVerbose());
                }
            };
        } catch (DependencyCollectionException e) {

        Activation activation = profile.getActivation();

        if (activation == null) {
            return false;
        }

        ActivationOS os = activation.getOs();

        if (os == null) {
            return false;
        }

        boolean active = ensureAtLeastOneNonNull(os);

    List<Exception> getExceptions();

    /**
     * Gets the root node of the dependency graph.
     *
     * @return the root node of the dependency graph or {@code null} if none
     */
    @Nullable
    Node getRoot();

import org.apache.maven.api.annotations.Provider;

/**
 * Represents a dependency node within a Maven project's dependency collector.
 *
 * @since 4.0.0
 * @see org.apache.maven.api.services.DependencyCollectorResult#getRoot()
 */
@Experimental
@Immutable
@Provider
public interface Node {

    /**
     * @return artifact for this node
     */
    @Nullable
    Artifact getArtifact();

    /**

    @Test
    void testValidateUniqueProxyId() throws Exception {
        Settings settings = new Settings();
        Proxy proxy = new Proxy();
        String id = "foo";
        proxy.setId(id);
        proxy.setHost("www.example.com");
        settings.addProxy(proxy);
        settings.addProxy(proxy);

        SimpleProblemCollector problems = new SimpleProblemCollector();
        validator.validate(settings, problems);

                                    return r.getCollectionErrors();
                                }

                                @Override
                                public Node getRoot() {
                                    return session.getNode(r.getDependencyGraph());
                                }
                            });
                }
            };

        DependencyCollectorResult collectorResult =
                session.getService(DependencyCollector.class).collect(request);
        List<Node> nodes = flatten(session, collectorResult.getRoot(), request.getPathScope());
        List<ArtifactCoordinate> coordinates = nodes.stream()
                .map(Node::getDependency)
                .filter(Objects::nonNull)
                .map(Artifact::toCoordinate)

            collect.setTrace(RequestTrace.newChild(trace, depRequest));
            node = repoSystem.collectDependencies(session, collect).getRoot();
            result.setDependencyGraph(node);
        } catch (DependencyCollectionException e) {
            result.setDependencyGraph(e.getResult().getRoot());
            result.setCollectionErrors(e.getResult().getExceptions());

            throw new DependencyResolutionException(