/**
     * Gets the class loader from which to load any types referenced by the configuration. If unset, the class loader of
     * the bean class will be used.
     *
     * @return The class loader to load referenced types from or {@code null} if unset.
     */
    ClassLoader getClassLoader();

    /**

    public static CoreExtensionEntry discoverFrom(ClassRealm loader) {
        Set<String> artifacts = new LinkedHashSet<>();
        Set<String> packages = new LinkedHashSet<>();

        try {
            Enumeration<URL> urls = loader.getResources(BUILDER.getExtensionDescriptorLocation());
            while (urls.hasMoreElements()) {

        <executions>
          <execution>
            <id>load</id>
            <phase>validate</phase>
            <configuration>
              <resourcePaths>org/apache/maven/its/mng3906/SomeClass.class</resourcePaths>
              <pluginClassLoaderOutput>target/pcl.properties</pluginClassLoaderOutput>
            </configuration>
            <goals>
              <goal>load</goal>
            </goals>
          </execution>

        URL myResource = ExpressionDocumenter.class.getClassLoader().getResource(myResourcePath);

        assert myResource != null : "The resource is this class itself loaded by its own classloader and must exist";

        String myClasspathEntry = myResource.getPath();

        myClasspathEntry = myClasspathEntry.substring(0, myClasspathEntry.length() - (myResourcePath.length() + 2));

    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.

    /**
     * <p>
     * PluginId =&gt; ExtensionRealmCache.CacheRecord map MavenProject context value key. The map is used to ensure the
     * 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
     */

import java.nio.file.Path;

import org.apache.maven.api.annotations.Nonnull;
import org.apache.maven.api.annotations.Nullable;

import static org.apache.maven.api.services.BaseRequest.nonNull;

/**
 * A Source specific to load POMs.  The {@link #resolve(ModelLocator, String)} method
 * will be used to find POMs for children modules.
 *
 * @since 4.0.0
 */
public interface ModelSource extends Source {

    interface ModelLocator {

        File pom0 = new File(localRepo, "p0/pom.xml");

        File pom0Basedir = pom0.getParentFile();

        File pom1 = new File(pom0Basedir, "p1/pom.xml");

        // load everything...
        MavenProject project0 = getProject(pom0);
        MavenProject project1 = getProject(pom1);

        assertEquals(pom0Basedir, project1.getParent().getBasedir());
    }

        File pom0 = new File(localRepo, "p0/pom.xml");
        File pom0Basedir = pom0.getParentFile();
        File pom1 = new File(pom0Basedir, "p1/pom.xml");

        // load the child project, which inherits from p0...
        MavenProject project0 = getProjectWithDependencies(pom0);
        MavenProject project1 = getProjectWithDependencies(pom1);

                            .getLifecycleMappings()
                            .values()));
                } catch (Exception e) {
                    throw new RuntimeException("Unable to load plugin lifecycles", e);
                }
            }

            @Override
            public ClassLoader getClassLoader() {
                return delegate.getMojoDescriptor().getRealm();
            }