* without requiring the XML to be parsed. For build sources, this typically
     * returns {@code null} since the coordinates are determined by parsing the POM.
     *
     * @return the model identifier, or {@code null} if not available or not applicable
     * @since 4.0.0
     */
    @Nullable
    default String getModelId() {
        return null;
    }

    /**
     * Interface for locating POM files within a project structure.

    assertTrue("add(null) should return true", collection.add(null));
    expectAdded((E) null);
  }

  @CollectionFeature.Require(value = SUPPORTS_ADD, absent = ALLOWS_NULL_VALUES)
  public void testAdd_nullUnsupported() {
    assertThrows(NullPointerException.class, () -> collection.add(null));
    expectUnchanged();
    expectNullMissingWhenNullUnsupported("Should not contain null after unsupported add(null)");
  }

        MavenSession session = new MavenSession(
                getContainer(), repoSession, new DefaultMavenExecutionRequest(), new DefaultMavenExecutionResult());
        session.setSession(defaultSessionFactory.newSession(session));

        DefaultSession s = new DefaultSession(session, null, null, null, null, null);

        .testEquals();
  }

  @AndroidIncompatible // Android forbids null parent ClassLoader
  public void testClassPathEntries_emptyURLClassLoader_noParent() {
    assertThat(ClassPath.getClassPathEntries(new URLClassLoader(new URL[0], null)).keySet())
        .isEmpty();
  }

  @AndroidIncompatible // Android forbids null parent ClassLoader
  public void testClassPathEntries_urlClassLoader_noParent() throws Exception {

        @Override
        public void onEndElement(String elementName) {
            if (elementName.equals("table")) {
                currentTable = null;
                header = null;
            }
            if (elementName.equals("tr")) {
                currentRow = null;
            }
            nodes.pop();
        }

        @Override
        public void onText(String text) {

      val sslContextClass = Class.forName("sun.security.ssl.SSLContextImpl")
      val context = readFieldOrNull(sslSocketFactory, sslContextClass, "context") ?: return null
      readFieldOrNull(context, X509TrustManager::class.java, "trustManager")
    } catch (e: ClassNotFoundException) {
      null
    } catch (e: RuntimeException) {
      // Throws InaccessibleObjectException (added in JDK9) on JDK 17 due to

   * the call to {@code contains(null)} is permitted to throw a {@code NullPointerException}.
   *
   * @param message message to use upon assertion failure
   */
  protected void expectNullKeyMissingWhenNullKeysUnsupported(String message) {
    try {
      assertFalse(message, getMap().containsKey(null));
    } catch (NullPointerException tolerated) {

        Reporting reporting = model.getReporting();

        if (reporting != null) {
            for (ReportPlugin reportPlugin : reporting.getPlugins()) {
                Xpp3Dom parentDom = (Xpp3Dom) reportPlugin.getConfiguration();

                if (parentDom != null) {
                    for (ReportSet execution : reportPlugin.getReportSets()) {

            object = xpp3Dom.getDom();
        }
        if (object instanceof XmlNode xmlNode) {
            return new Xpp3DomNodePointer(xmlNode);
        }
        return null;
    }

    @Override
    public NodePointer createNodePointer(NodePointer parent, QName name, Object object) {
        if (object instanceof org.codehaus.plexus.util.xml.Xpp3Dom xpp3Dom) {

    graph.putEdgeValue(4, 4, "valueD");

    assertThat(graph.edgeValueOrDefault(1, 2, null)).isEqualTo("valueA");
    assertThat(graph.edgeValueOrDefault(2, 1, null)).isEqualTo("valueB");
    assertThat(graph.edgeValueOrDefault(2, 3, null)).isEqualTo("valueC");
    assertThat(graph.edgeValueOrDefault(4, 4, null)).isEqualTo("valueD");
    assertThat(graph.edgeValueOrDefault(1, 2, DEFAULT)).isEqualTo("valueA");