/**
     * Method addExtension.
     *
     * @param coreExtension a coreExtension object.
     */
    public void addExtension(CoreExtension coreExtension) {
        getExtensions().add(coreExtension);
    } // -- void addExtension( CoreExtension )

    /**
     * Method getExtensions.
     *
     * @return List
     */
    public List<CoreExtension> getExtensions() {
        if (this.extensions == null) {

                String key = coreExtension.getGroupId() + ":" + coreExtension.getArtifactId();
                CoreExtension conflict = selectedExtensions.putIfAbsent(key, coreExtension);
                if (conflict != null && !Objects.equals(coreExtension.getVersion(), conflict.getVersion())) {
                    conflicts.add(String.format(

        if ((coreExtensions.getExtensions() != null)
                && (coreExtensions.getExtensions().size() > 0)) {
            for (Iterator iter = coreExtensions.getExtensions().iterator(); iter.hasNext(); ) {
                CoreExtension o = (CoreExtension) iter.next();
                writeCoreExtension(o, "extension", serializer);
            }
        }

 * @see Constants#MAVEN_INSTALLATION_EXTENSIONS
 */
@Experimental
public record CoreExtensions(Path source, List<CoreExtension> coreExtensions) {
    public CoreExtensions(Path source, List<CoreExtension> coreExtensions) {
        this.source = requireNonNull(source, "source");
        this.coreExtensions = requireNonNull(coreExtensions, "coreExtensions");
    }

            Set<String> providedArtifacts,
            List<CoreExtension> configuration,
            UnaryOperator<String> interpolator)
            throws Exception {
        List<CoreExtensionEntry> extensions = new ArrayList<>();

        DependencyFilter dependencyFilter = new ExclusionsDependencyFilter(providedArtifacts);

        for (CoreExtension extension : configuration) {
            List<Artifact> artifacts =

            Set<String> providedArtifacts,
            List<CoreExtension> configuration,
            UnaryOperator<String> interpolator)
            throws Exception {
        List<LoadedCoreExtension> extensions = new ArrayList<>();

        DependencyFilter dependencyFilter = new ExclusionsDependencyFilter(providedArtifacts);

        for (CoreExtension extension : configuration) {
            List<Artifact> artifacts =

          <version>1.0.0+</version>
          <association xml.itemsStyle="flat">
            <type>CoreExtension</type>
            <multiplicity>*</multiplicity>
          </association>
        </field>
      </fields>
    </class>
    <class xml.tagName="extension">
      <name>CoreExtension</name>
      <description>Describes a build extension to utilise.</description>
      <version>1.0.0+</version>

package org.apache.maven.cli.internal;

import org.apache.maven.cli.internal.extension.model.CoreExtension;

/**
 * Exception occurring trying to resolve a plugin.
 *
 */
@Deprecated
public class ExtensionResolutionException extends Exception {

    private final CoreExtension extension;

    public ExtensionResolutionException(CoreExtension extension, Throwable cause) {
        super(

import com.google.inject.Module;
import org.apache.maven.api.Constants;
import org.apache.maven.api.ProtoSession;
import org.apache.maven.api.cli.Logger;
import org.apache.maven.api.cli.extensions.CoreExtension;
import org.apache.maven.api.services.MessageBuilderFactory;
import org.apache.maven.api.services.SettingsBuilder;
import org.apache.maven.cling.extensions.BootstrapCoreExtensionManager;

import org.apache.maven.BuildAbort;
import org.apache.maven.InternalErrorException;
import org.apache.maven.Maven;
import org.apache.maven.api.Constants;
import org.apache.maven.api.cli.extensions.CoreExtension;
import org.apache.maven.api.cli.extensions.InputSource;
import org.apache.maven.api.services.MessageBuilder;
import org.apache.maven.api.services.MessageBuilderFactory;
import org.apache.maven.building.FileSource;