/**
     * 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();

    /**
     * Sets the class loader from which to load any types referenced by the configuration. If unset, the class loader of

        <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>

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();
            }

        this.packages = Collections.unmodifiableSet(new HashSet<>(packages));
        this.key = key;
        this.configuration = configuration;
    }

    /**
     * Returns ClassLoader used to load extension classes.
     */
    public ClassRealm getClassRealm() {
        return realm;
    }

    /**
     * Returns artifacts exported by the extension, identified by groupId:artifactId string key.
     */

    private static final String EXPRESSION_DOCO_ROOTPATH = "META-INF/maven/plugin-expressions/";

    private static Map<String, Expression> expressionDocumentation;

    public static Map<String, Expression> load() throws ExpressionDocumentationException {
        if (expressionDocumentation == null) {
            expressionDocumentation = new HashMap<>();

            ClassLoader docLoader = initializeDocLoader();

        <executions>
          <execution>
            <id>load</id>
            <phase>validate</phase>
            <configuration>
              <resourcePaths>maven-core-it.properties</resourcePaths>
              <pluginClassLoaderOutput>target/pcl.properties</pluginClassLoaderOutput>
            </configuration>
            <goals>
              <goal>load</goal>
            </goals>
          </execution>

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

        File pom0Basedir = pom0.getParentFile();

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

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

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