Extension descriptor, stored in <code>META-INF/maven/extension.xml</code> in an extension's jar artifact to
    precisely control parts of the extension and dependencies to expose in the API class loader.
    Maven uses Plexus Classworlds to build the class loader hierarchy, therefore some concepts used in this extensions
    stem from Plexus Classworlds originally.

            ExpressionEvaluator evaluator,
            ClassLoader loader,
            ConfigurationListener listener)
            throws ComponentConfigurationException {
        new EnhancedConfigurationConverter()
                .processConfiguration(
                        converterLookup,
                        component,
                        loader, //
                        configuration,
                        evaluator,

            if (null == value && implType.isInterface() && configuration.getChildCount() == 0) {
                return null; // nothing to process
            }
            final Object bean = instantiateObject(implType);
            if (null == value) {
                processConfiguration(lookup, bean, loader, configuration, evaluator, listener);
            } else {

configuration attributes on the instantiated LogFactory instance. Once an implementation class name is selected, the corresponding class is loaded from the current Thread context class loader (if there is one), or from the class loader that loaded the LogFactory class itself otherwise. This allows a copy of commons-logging.jar to be shared in a multiple class loader environment (such as a servlet container), but still allow each web application to provide its own LogFactory implementation, if it so desires....

og, java.io.Serializable { private static org.apache.avalon.framework.logger.Logger defaultLogger; private transient org.apache.avalon.framework.logger.Logger logger; private String name; public void AvalonLogger(org.apache.avalon.framework.logger.Logger); public void AvalonLogger(String); public org.apache.avalon.framework.logger.Logger getLogger(); public static void setDefaultLogger(org.apache.avalon.framework.logger.Logger); public void debug(Object, Throwable); public void debug(Object); public...

    }

    protected static File getFileForClasspathResource(String resource)
            throws FileNotFoundException, URISyntaxException {
        ClassLoader cloader = Thread.currentThread().getContextClassLoader();

        URL resourceUrl = cloader.getResource(resource);

        if (resourceUrl == null) {
            throw new FileNotFoundException("Unable to find: " + resource);
        }

    final Map<Path, Holder> modelByPath = new ConcurrentHashMap<>();

    final Map<GAKey, Holder> modelByGA = new ConcurrentHashMap<>();

    public static class Holder {
        private volatile boolean set;
        private volatile Model model;

        Holder() {}

        Holder(Model model) {
            this.model = Objects.requireNonNull(model);

                Model model = findRawModel(from, gId, aId);
                if (model != null) {
                    context.modelByGA.put(new GAKey(gId, aId), new Holder(model));
                    context.modelByPath.put(model.getPomFile(), new Holder(model));
                }
                return model;
            }

            @Override
            public Model getRawModel(Path from, Path path) {

        logger.debug("Populating class realm {}", classRealm.getId());

        for (ClassRealmConstituent constituent : constituents) {
            File file = constituent.getFile();

            if (logger.isDebugEnabled()) {
                String id = getId(constituent);
                logger.debug("  Included: {}", id);
            }

            try {

    boolean isTwoPhaseBuilding();

    boolean isLocationTracking();

    /**
     * Indicates if the model to be built is a local project or a dependency.
     * In case the project is loaded externally from a remote repository (as a dependency or
     * even as an external parent), the POM will be parsed in a lenient way.  Local POMs
     * are parsed more strictly.
     */
    boolean isProjectBuild();