* @return The project's class realm or {@code null}.
     */
    public ClassRealm getClassRealm() {
        return classRealm;
    }

    /**
     * Sets the artifact filter used to exclude shared extension artifacts from plugin realms. <strong>Warning:</strong>
     * This is an internal utility method that is only public for technical reasons, it is not part of the public API.

    /**
     * This default mode for combining children DOMs during merge means that where element names match, the process will
     * try to merge the element data, rather than putting the dominant and recessive elements (which share the same
     * element name) as siblings in the resulting DOM.
     */
    String DEFAULT_CHILDREN_COMBINATION_MODE = CHILDREN_COMBINATION_MERGE;

    String SELF_COMBINATION_MODE_ATTRIBUTE = "combine.self";

    server processes which work by conversing over a port may fail.

  * Not all "remote" repositories will fail. Specifically, if the remote
    repo uses the file:// protocol, and it doesn't refer to a shared
    filesystem, it will continue to be available.

  The question remaining is: Which level of offline mode will we support? It
  seems reasonable to assume that users will be able to tell when localhost is

         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <!-- Shared parent. Doesn't define a lot of things about Apache like general mailing lists, but does
       define the settings common to all projects at Apache -->
  <groupId>org.apache</groupId>
  <artifactId>apache</artifactId>

import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
import org.apache.maven.metadata.v4.MetadataStaxReader;
import org.apache.maven.metadata.v4.MetadataStaxWriter;

/**
 * Shared methods of the repository metadata handling.
 *
 */
@Deprecated
public abstract class AbstractRepositoryMetadata implements RepositoryMetadata {
    private static final String LS = System.lineSeparator();

     * @param artifactId never {@code null}
     * @param version can be {@code null}
     * @return the matching model or {@code null}
     * @throws IllegalStateException if version was null and multiple modules share the same groupId + artifactId
     */
    public Model get(String groupId, String artifactId, String version) {
        return modelsByGa.getOrDefault(new GAKey(groupId, artifactId), Collections.emptySet()).stream()

     */
    @Nonnull
    @Override
    public String option(Iterable<? extends Path> paths) {
        return format(null, paths);
    }

    /**
     * Implementation shared with {@link Modular}.
     */
    String format(String moduleName, Iterable<? extends Path> paths) {
        if (option == null) {
            throw new IllegalStateException("No option is associated to this path type.");

 * is thread safe.
 * <p>
 * Important: Given the instance of supplier memorizes the supplier {@link RepositorySystem} instance it supplies,
 * their lifecycle is shared as well: once supplied repository system is shut-down, this instance becomes closed as
 * well. Any subsequent {@code getXXX} method invocation attempt will fail with {@link IllegalStateException}.
 */

              <exclude>src/assembly/shared/init</exclude>
              <exclude>src/assembly/shared/init.cmd</exclude>
              <exclude>src/assembly/shared/mvnlauncher</exclude>
              <exclude>src/assembly/shared/mvnlauncher.cmd</exclude>
              <exclude>src/assembly/shared/mvnvalidate</exclude>
              <exclude>src/assembly/shared/mvnvalidate.cmd</exclude>

implementation class name is selected, the corresponding class is loaded from the current Thread context class loader (if there is one), or from the class loader that loaded the LogFactory class itself otherwise. This allows a copy of commons-logging.jar to be shared in a multiple class loader environment (such as a servlet container), but still allow each web application to provide its own LogFactory implementation, if it so desires. An instance of this class will then be created, and cached per class loader....