* supplied by the user of the class. For example, {@code Multiset.Entry.getElement()} returns
 * {@code @ParametricNullness E}, which means:
 *
 * <ul>
 *   <li>{@code getElement} on a {@code Multiset.Entry<@NonNull String>} returns {@code @NonNull
 *       String}.
 *   <li>{@code getElement} on a {@code Multiset.Entry<@Nullable String>} returns {@code @Nullable
 *       String}.
 * </ul>
 *

 * supplied by the user of the class. For example, {@code Multiset.Entry.getElement()} returns
 * {@code @ParametricNullness E}, which means:
 *
 * <ul>
 *   <li>{@code getElement} on a {@code Multiset.Entry<@NonNull String>} returns {@code @NonNull
 *       String}.
 *   <li>{@code getElement} on a {@code Multiset.Entry<@Nullable String>} returns {@code @Nullable
 *       String}.
 * </ul>
 *

     */
    @Nonnull
    Optional<List<String>> goals();

    /**
     * Returns the target POM model version for upgrades.
     * Supported values include "4.0.0" and "4.1.0".
     *
     * @return an {@link Optional} containing the model version, or empty if not specified
     */
    @Nonnull
    Optional<String> modelVersion();

    /**

     * Obtain the {@link ClassRealm} used for Maven Core.
     *
     * @return the class realm of core.
     */
    @Nonnull
    ClassRealm getRealm();

    /**
     * Shorthand method to obtain the {@link ClassWorld} used for Maven Core.
     *
     * @return the class world in use.
     */
    @Nonnull
    default ClassWorld getClassWorld() {
        return getRealm().getWorld();
    }

    extends Map<Class<? extends @NonNull B>, B> {
  /**
   * Returns the value the specified class is mapped to, or {@code null} if no entry for this class
   * is present. This will only return a value that was bound to this specific class, not a value
   * that may have been bound to a subtype.
   */
  <T extends @NonNull B> @Nullable T getInstance(Class<T> type);

  /**

     * if there are parser errors, this request may not be fully processed and should immediately be failed.
     */
    @Nonnull
    InvokerRequest parseInvocation(@Nonnull ParserRequest parserRequest);

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

public interface Lookup extends Service {
    /**
     * Performs a lookup for given typed component.
     *
     * @param type The component type.
     * @return The component.
     * @param <T> The component type.
     * @throws LookupException if no such component or there is some provisioning related issue.
     */
    @Nonnull
    <T> T lookup(Class<T> type);

    /**

         * Returns the name of this phase.
         *
         * @return the phase name
         */
        @Nonnull
        String name();

        /**
         * Returns the list of plugins bound to this phase.
         *
         * @return the list of plugins
         */
        @Nonnull
        List<Plugin> plugins();

        /**

     *         {@code null}.
     */
    @Nonnull
    String getModelId();

    /**
     * Gets the applicable maven version/validation level of this problem
     * @return The version, never {@code null}.
     */
    @Nonnull
    Version getVersion();

 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.cling.invoker;

import java.util.List;

import org.apache.maven.api.annotations.Nonnull;
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()}.
 *