// namespaced indicates if a resource is namespaced or not.
  optional bool namespaced = 2;

  // group is the preferred group of the resource.  Empty implies the group of the containing resource list.
  // For subresources, this may have a different value, for example: Scale".
  optional string group = 8;

  // version is the preferred version of the resource.  Empty implies the version of the containing resource list

<project>
  <modelVersion>4.0.0</modelVersion>
  <artifactId>foo</artifactId>
  <groupId>foo</groupId>
  <version>99.44</version>
  <packaging>jar</packaging>

  <dependencies>
    <dependency>
      <groupId>gid</groupId>
      <artifactId>aid</artifactId>
      <version>1.0</version>
      <exclusions>
        <exclusion>
          <groupId></groupId>
        </exclusion>
      </exclusions>
    </dependency>

    @Nonnull
    default Artifact create(
            @Nonnull Session session, String groupId, String artifactId, String version, String extension) {
        return create(ArtifactFactoryRequest.build(session, groupId, artifactId, version, extension));
    }

    @Nonnull
    default Artifact create(
            @Nonnull Session session,
            String groupId,
            String artifactId,
            String version,

specific language governing permissions and limitations
under the License.
-->

<project>
  <parent>
    <artifactId>p3</artifactId>
    <groupId>maven.t02</groupId>
    <version>1.0</version>
  </parent>
  <modelVersion>4.0.0</modelVersion>
  <groupId>maven.t02</groupId>
  <artifactId>p4</artifactId>
  <packaging>pom</packaging>
  <name>p4</name>
  <version>1.0</version>

                            groupId, artifactId, a.getLocation(), b.getLocation()));
                })
                .orElse(null);
    }

    public void putSource(String groupId, String artifactId, FileModelSource source) {
        mappedSources
                .computeIfAbsent(groupId + ":" + artifactId, k -> new HashSet<>())
                .add(source);
        if (groupId != null) {

    protected AbstractArtifactResolutionException(
            String message,
            String groupId,
            String artifactId,
            String version,
            String type,
            String classifier,
            List<ArtifactRepository> remoteRepositories,
            List<String> path) {
        this(message, groupId, artifactId, version, type, classifier, remoteRepositories, path, null);
    }

                            if (Objects.equals(artifact.getGroupId(), groupId)
                                    && Objects.equals(artifact.getArtifactId(), artifactId)) {
                                // here groupId and artifactId cannot be null
                                return new PluginInfo(groupId, artifactId, goalPrefix, name);
                            } else {

  <modelVersion>4.0.0</modelVersion>

  <groupId>org.apache.maven.its.it0063</groupId>
  <artifactId>maven-it-it0063</artifactId>
  <version>1.0</version>
  <packaging>jar</packaging>

  <name>Maven Integration Test :: it0063</name>
  <description>Test the use of a system scoped dependency to a (fake) tools.jar.</description>

  <dependencies>
    <dependency>
      <groupId>com.sun</groupId>
      <artifactId>tools</artifactId>

  <modelVersion>4.0.0</modelVersion>
  <parent>
    <groupId>org.apache.maven.validation</groupId>
    <artifactId>parent</artifactId>
    <version>1</version>
  </parent>

  <groupId>org.apache.maven.validation</groupId>
  <artifactId>project</artifactId>
  <version>1.0.0-SNAPSHOT</version>

  <properties>
    <x>just/some/path</x>
  </properties>

  <modelVersion>4.0.0</modelVersion>

  <parent>
    <groupId>com.example.group</groupId>
    <artifactId>com-parent</artifactId>
    <version>LATEST</version>
  </parent>
  <groupId>com.example.group</groupId>
  <artifactId>valid-version-wrong</artifactId>
  <version>1.0</version>

  <description>