* 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
     */
    public static final String KEY_EXTENSIONS_REALMS = DefaultMavenPluginManager.class.getName() + "/extensionsRealms";

          </description>
          <type>String</type>
        </field>
        <field>
          <name>extensions</name>
          <version>4.0.0+</version>
          <description>A set of build extensions to use from this project.</description>
          <association>
            <type>Extension</type>
            <multiplicity>*</multiplicity>
          </association>
        </field>
      </fields>

  </parent>

  <artifactId>maven-api</artifactId>
  <packaging>pom</packaging>
  <name>Maven 4 API</name>
  <description>A new immutable API for Maven 4 to better manage what plugins and extensions can influence.</description>

  <modules>
    <module>maven-api-meta</module>
    <module>maven-api-di</module>
    <module>maven-api-xml</module>
    <module>maven-api-model</module>

     * <p>
     * This type registry is NOT used by Maven Core: Maven replaces it during Session creation with a type registry
     * that supports extending it (i.e. via Maven Extensions).
     * <p>
     * Important: this "static" list of types should be in-sync with core provided types.
     */
    protected ArtifactTypeRegistry getArtifactTypeRegistry() {

            // extensionArtifacts
            Set<Artifact> extensionArtifacts = new HashSet<>();
            List<Extension> extensions =
                    project.getModel().getDelegate().getBuild().getExtensions();
            if (extensions != null) {
                for (Extension ext : extensions) {
                    String version;
                    if (ext.getVersion() == null || ext.getVersion().isEmpty()) {

     * @param extension the artifact extension, or {@code null} is unspecified
     * @return artifact with the given coordinates
     *
     * @see org.apache.maven.api.services.ArtifactFactory#create(Session, String, String, String, String)
     */
    @Nonnull
    Artifact createArtifact(String groupId, String artifactId, String version, String extension);

    /**

                session.createArtifactCoordinate("org.apache.maven.core.test", "test-extension", "1", "jar"));

        List<Path> paths = session.resolveDependencies(coord);

        assertNotNull(paths);
        assertEquals(10, paths.size());
        assertEquals("test-extension-1.jar", paths.get(0).getFileName().toString());

  define for each {{{../maven-model/maven.html#class_dependency}dependency type}} information on the artifact
  (classifier, extension, language) and how to manage it as dependency (add to classpath, include dependencies).

  They are replaced in Maven 4 with Maven 4 API Core's {{{../api/maven-api-core/apidocs/org/apache/maven/api/Type.html}Dependency Types}},

import org.codehaus.plexus.component.repository.exception.ComponentLookupException;
import org.codehaus.plexus.testing.PlexusTest;
import org.eclipse.sisu.Typed;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.extension.ExtendWith;
import org.mockito.Mock;
import org.mockito.junit.jupiter.MockitoExtension;

import static org.junit.jupiter.api.Assertions.assertNotNull;
import static org.junit.jupiter.api.Assertions.assertNotSame;

        String groupId = artifact.getGroupId();
        String artifactId = artifact.getArtifactId();
        String version = artifact.getBaseVersion();
        String classifier = artifact.getClassifier();
        String extension = artifact.getExtension();
        Path repo = getProjectLocalRepo();
        return repo.resolve(groupId)
                .resolve(artifactId)
                .resolve(version)
                .resolve(artifactId