protected final RepositorySystemSession session;
    protected final RepositorySystem repositorySystem;
    protected final List<RemoteRepository> repositories;
    protected final Lookup lookup;
    private final Map<Class<? extends Service>, Service> services = new ConcurrentHashMap<>();
    private final List<Listener> listeners = new CopyOnWriteArrayList<>();

    private final List<Listener> listeners = new CopyOnWriteArrayList<>();
    private final Map<org.eclipse.aether.graph.DependencyNode, Node> allNodes =
            Collections.synchronizedMap(new WeakHashMap<>());
    private final Map<org.eclipse.aether.artifact.Artifact, Artifact> allArtifacts =
            Collections.synchronizedMap(new WeakHashMap<>());