@Nonnull
    Map<String, String> getUserProperties();

    /**
     * Returns immutable system properties to use for interpolation. The system properties are collected from the
     * runtime environment such as {@link System#getProperties()} and environment variables
     * (prefixed with {@code env.}).
     *
     * @return the system properties, never {@code null}
     */
    @Nonnull
    Map<String, String> getSystemProperties();

    }

    //
    // Implementation
    //

    private File findArtifact(MavenProject project, Artifact artifact) {
        // POMs are always returned from the file system
        if ("pom".equals(artifact.getExtension())) {
            return project.getFile();
        }

        // First check in the project local repository

        session.setArtifactDescriptorPolicy(getArtifactDescriptorPolicy());
        session.setScopeManager(getScopeManager());
    }

    /**
     * Creates a new Maven-like repository system session by initializing the session with values typical for
     * Maven-based resolution. In more detail, this method configures settings relevant for the processing of dependency

import org.eclipse.aether.RepositoryCache;
import org.eclipse.aether.RepositorySystemSession;

import static java.util.Objects.requireNonNull;

/**
 * A model builder cache backed by the repository system cache.
 *
 */
public class DefaultModelCache implements ModelCache {
    private static final String KEY = DefaultModelCache.class.getName();

    @SuppressWarnings("unchecked")

    /**
     * List of profile ids that have been explicitly deactivated by the user.
     */
    @Nonnull
    List<String> getInactiveProfileIds();

    /**
     * Provides a map of system properties.
     */
    @Nonnull
    Map<String, String> getSystemProperties();

    /**
     * Provides a map of user properties.
     * User properties
     */
    @Nonnull

      return this;
    }

    @CanIgnoreReturnValue
    Builder<K, V> combine(Builder<K, V> other) {
      checkNotNull(other);
      ensureCapacity(this.size + other.size);
      System.arraycopy(
          other.alternatingKeysAndValues,
          0,
          this.alternatingKeysAndValues,
          this.size * 2,
          other.size * 2);
      this.size += other.size;
      return this;

 * thrown away immediately once repository system was created and there is no need for more instances. If new
 * repository system instance needed, new instance of this class must be created. For proper shut down of returned
 * repository system instance(s) use {@link RepositorySystem#shutdown()} method on supplied instance(s).
 * <p>

            d.setGroupId(groupId);
            d.setArtifactId(artifactId);
            d.setVersion(version);
            d.setScope(scope);

            if (systemPath != null && scope.equals(Artifact.SCOPE_SYSTEM)) {
                d.setSystemPath(systemPath);
            }

            if (exclusion != null) {
                d.addExclusion(exclusion);
            }

            project.getDependencies().add(d);

    Object[] elements = new Object[paramCount + others.length];
    elements[0] = e1;
    elements[1] = e2;
    elements[2] = e3;
    elements[3] = e4;
    elements[4] = e5;
    elements[5] = e6;
    System.arraycopy(others, 0, elements, paramCount, others.length);
    return construct(elements.length, elements);
  }

  /**
   * Constructs an {@code ImmutableSet} from the first {@code n} elements of the specified array. If

   *       public Double apply(Integer in) {
   *         return Math.sqrt((int) in);
   *       }
   *     };
   * Map<String, Double> transformed = Maps.transformValues(map, sqrt);
   * System.out.println(transformed);
   * }</pre>
   *
   * ... prints {@code {a=2.0, b=3.0}}.
   *
   * <p>Changes in the underlying map are reflected in this view. Conversely, this view supports