* Create a key using the given class as an identifier and as the type of the object.
     */
    static <T> Key<T> key(Class<T> clazz) {
        return new Key<>(clazz, clazz);
    }

    /**
     * Create a key using the given class and id.
     */
    static <T> Key<T> key(Class<T> clazz, Object id) {
        return new Key<>(clazz, id);
    }

    /**
     * Key used to query the session data

                    //noinspection unchecked
                    return () -> (Q) list(list);
                }
                if (key.getRawType() == Map.class) {
                    Key<?> k = key.getTypeParameter(0);
                    Key<Object> v = key.getTypeParameter(1);
                    if (k.getRawType() == String.class) {
                        Set<Binding<Object>> res2 = getBindings(v);

    }

    @Override
    public boolean equals(Object o) {
        return o instanceof Artifact && Objects.equals(key(), ((Artifact) o).key());
    }

    @Override
    public int hashCode() {
        return key.hashCode();
    }

    @Override
    public String toString() {
        return artifact.toString();
    }

    private static final String ISSUES_KEY = DefaultPluginValidationManager.class.getName() + ".issues";

    private static final String PLUGIN_EXCLUDES_KEY = DefaultPluginValidationManager.class.getName() + ".excludes";

    private static final String MAVEN_PLUGIN_VALIDATION_KEY = "maven.plugin.validation";

    private static final String MAVEN_PLUGIN_VALIDATION_EXCLUDES_KEY = "maven.plugin.validation.excludes";

     * same class realm is used to load build extensions and load mojos for extensions=true plugins.
     * </p>
     * <strong>Note:</strong> This is part of internal implementation and may be changed or removed without notice
     *
     * @since 3.3.0
     */

            for (Plugin plugin : plugins) {
                Object key = plugin.getKey();
                Plugin first = normalized.get(key);
                if (first != null) {
                    plugin = merger.mergePlugin(plugin, first);
                }
                normalized.put(key, plugin);
            }

            if (plugins.size() != normalized.size()) {

    private static final SessionData.Key<ProjectIndex> PROJECT_INDEX = SessionData.key(ProjectIndex.class);

    @SuppressWarnings({"unchecked", "rawtypes"})
    private static final SessionData.Key<Map<MavenProject, OwnerReentrantLock>> PROJECT_LOCKS =
            (SessionData.Key) SessionData.key(Map.class, ProjectLock.class);

    private final BuildPluginManager pluginManager;

                        String key = plugin.getKey();
                        managedVersions.computeIfAbsent(key, k -> plugin.getVersion());
                    }
                }
            }
        }

        for (String key : versions.keySet()) {
            if (versions.get(key) == null && managedVersions.get(key) == null) {

        Key key = new CacheKey(
                project,
                project.getRemoteProjectRepositories(),
                scopesToCollect,
                scopesToResolve,
                aggregating,
                session);
        return keys.computeIfAbsent(key, k -> k);
    }

    @Override
    public CacheRecord get(Key key) throws LifecycleExecutionException {

                    Object key = getPluginExecutionKey().apply(element);
                    merged.put(key, element);
                }

                for (PluginExecution element : src) {
                    Object key = getPluginExecutionKey().apply(element);
                    PluginExecution existing = merged.get(key);
                    if (existing != null) {