this.source = requireNonNull(source, "source");
        this.coreExtensions = requireNonNull(coreExtensions, "coreExtensions");
    }

import java.util.List;

/**
 * Extensions to load.
 *
 * @deprecated Use {@link org.apache.maven.api.cli.extensions.CoreExtension} instead
 */
@Deprecated
@SuppressWarnings("all")
public class CoreExtensions implements Serializable {

    // --------------------------/
    // - Class/Member Variables -/
    // --------------------------/

    /**
     * Field extensions.
     */

        serializer.startDocument(coreExtensions.getModelEncoding(), null);
        writeCoreExtensions(coreExtensions, "extensions", serializer);
        serializer.endDocument();
    } // -- void write( Writer, CoreExtensions )

    /**
     * Method write.
     *
     * @param stream a stream object.
     * @param coreExtensions a coreExtensions object.
     * @throws IOException IOException if any.
     */

        Optional<List<CoreExtensions>> coreExtensions = context.invokerRequest.coreExtensions();
        if (coreExtensions.isEmpty() || coreExtensions.get().isEmpty()) {
            return List.of();
        }

        return selectCoreExtensions(
                context, context.invokerRequest.coreExtensions().orElseThrow());
    }

    /**

    }

    @Override
    public Optional<Path> rootDirectory() {
        return Optional.ofNullable(rootDirectory);
    }

    @Override
    public Optional<List<CoreExtensions>> coreExtensions() {
        return Optional.ofNullable(coreExtensions);
    }

    @Override
    public Optional<CIInfo> ciInfo() {
        return Optional.ofNullable(ciInfo);
    }

    public Optional<Options> options() {

     * @throws XmlPullParserException XmlPullParserException if
     * any.
     * @return CoreExtensions
     */
    private CoreExtensions parseCoreExtensions(XmlPullParser parser, boolean strict)
            throws IOException, XmlPullParserException {
        String tagName = parser.getName();
        CoreExtensions coreExtensions = new CoreExtensions();
        for (int i = parser.getAttributeCount() - 1; i >= 0; i--) {

     * {@link CoreExtensions} is validated, but the list elements may have overlapping elements, that requires
     * some logic to sort out (like precedence).
     * <p>
     * The list of {@link CoreExtensions} if present, is in precedence order.
     *
     * @return an {@link Optional} containing the {@link CoreExtensions}, or empty if not configured
     */
    @Nonnull

    protected abstract Options parseCliOptions(LocalContext context);

    /**
     * Important: This method must return list of {@link CoreExtensions} in precedence order.
     */
    protected List<CoreExtensions> readCoreExtensionsDescriptor(LocalContext context) {
        ArrayList<CoreExtensions> result = new ArrayList<>();
        Path file;
        List<CoreExtension> loaded;

  xml.namespace="http://maven.apache.org/EXTENSIONS/${version}"
  xml.schemaLocation="https://maven.apache.org/xsd/core-extensions-${version}.xsd">

  <id>core-extensions</id>
  <name>CoreExtensions</name>
  <description><![CDATA[
  <p>This is a reference for the Core Extensions descriptor.</p>
  <p>The default location for the Core Extensions descriptor file is <code>${maven.projectBasedir}/.mvn/extensions.xml</code></p>

import org.apache.maven.api.cli.InvokerRequest;
import org.apache.maven.api.cli.extensions.CoreExtension;

/**
 * Core extension selector: selects which entries to load from {@link InvokerRequest#coreExtensions()}.
 *
 * @param <C> The context type.
 */
public interface CoreExtensionSelector<C extends LookupContext> {
    /**
     * Selects core extensions to be loaded from list of all sources detected.
     */