modelVersion. This is required so that a change from modelVersion 4.0.0 to
  4.1.0 doesn't cause compatibility problems with users who have not upgraded
  their projects. It also allows for a certain amount of legacy support into the
  future. Therefore, we should rename this file from pom.xml in the maven-core
  jarfile to pom-4.0.0.xml (and successive revisions to the base pom made to

which might be interesting to read and for further discussion.

Getting Started
---------------

+ Make sure you have a [JIRA account](https://issues.apache.org/jira/).
+ Make sure you have a [GitHub account](https://github.com/signup/free).
+ If you're planning to implement a new feature, it makes sense to discuss your changes
  on the [dev list](https://maven.apache.org/mailing-lists.html) first.

import org.apache.maven.api.annotations.Nonnull;
import org.apache.maven.repository.internal.DefaultModelVersionParser;

import static org.apache.maven.internal.impl.Utils.nonNull;

/**
 * A wrapper class around a maven resolver artifact.
 */
public class DefaultArtifact implements Artifact {
    private final @Nonnull InternalSession session;
    private final @Nonnull org.eclipse.aether.artifact.Artifact artifact;

        }

        return pluginManager.getMojoDescriptor(
                plugin, goal, project.getRemotePluginRepositories(), session.getRepositorySession());
    }

    // TODO take repo mans into account as one may be aggregating prefixes of many
    // TODO collect at the root of the repository, read the one at the root, and fetch remote if something is missing
    // or the user forces the issue

          <version>4.0.0+</version>
          <description>
            Indicates the dependency is optional for use of this library. While the
            version of the dependency will be taken into account for dependency calculation if the
            library is used elsewhere, it will not be passed on transitively. Note: While the type
            of this field is {@code String} for technical reasons, the semantic type is actually

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

import static org.apache.maven.internal.impl.Utils.nonNull;

/**
 * A wrapper class around a maven resolver artifact.
 */
public class DefaultArtifactCoordinate implements ArtifactCoordinate {
    private final @Nonnull InternalSession session;
    private final @Nonnull org.eclipse.aether.artifact.Artifact coordinate;

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

import static org.apache.maven.internal.impl.Utils.nonNull;

/**
 * A wrapper class around a maven resolver artifact.
 */
public class DefaultArtifactCoordinate implements ArtifactCoordinate {
    private final @Nonnull InternalSession session;
    private final @Nonnull org.eclipse.aether.artifact.Artifact coordinate;

import org.apache.maven.artifact.repository.ArtifactRepository;
import org.apache.maven.artifact.versioning.OverConstrainedVersionException;

/**
 * Specific problems during resolution that we want to account for:
 * <ul>
 *   <li>missing metadata</li>
 *   <li>version range violations</li>
 *   <li>version circular dependencies</li>
 *   <li>missing artifacts</li>
 *   <li>network/transfer errors</li>

            // and this could lead to cycles where a thread waits for
            // a task to finish, then execute another one which waits
            // for the initial task...
            // In order to work around that problem, we override the
            // invokeAll method, so that whenever the method is called,
            // the pool core size will be incremented before submitting

import org.apache.maven.api.services.VersionParser;
import org.apache.maven.api.services.model.ModelVersionParser;

import static org.apache.maven.internal.impl.Utils.nonNull;

/**
 * A wrapper class around a resolver version that works as model version parser as well.
 */
@Named
@Singleton
public class DefaultVersionParser implements VersionParser {
    private final ModelVersionParser modelVersionParser;

    @Inject