// v1-->v2
        graph.addEdge(v1, v2, new MetadataGraphEdge("1.1", true, null, null, 2, 1));
        graph.addEdge(v1, v2, new MetadataGraphEdge("1.2", true, null, null, 2, 2));

        // v1-->v3
        graph.addEdge(v1, v3, new MetadataGraphEdge("1.1", true, null, null, 2, 1));
        graph.addEdge(v1, v3, new MetadataGraphEdge("1.2", true, null, null, 4, 2));

        // v3-->v4

    assertNull("getOrDefault(absent, null) should return null", getMap().getOrDefault(k3(), null));
  }

  @MapFeature.Require(ALLOWS_NULL_KEY_QUERIES)
  public void testGetOrDefault_absentNull() {
    assertEquals(
        "getOrDefault(null, def) should return the default value",
        v3(),
        getMap().getOrDefault(null, v3()));
  }

  @MapFeature.Require(absent = ALLOWS_NULL_KEY_QUERIES)

        if (project.getDependencyArtifacts() == null) {
            for (Dependency dependency : project.getDependencies()) {
                if (dependency.getGroupId() == null
                        || dependency.getGroupId().isEmpty()
                        || dependency.getArtifactId() == null
                        || dependency.getArtifactId().isEmpty()

              "options": {
                "match": "null",
                "result": {
                  "text": "N/A"
                }
              },
              "type": "special"
            }
          ],
          "thresholds": {
            "mode": "percentage",
            "steps": [
              {
                "color": "green",
                "value": null
              }
            ]
          },

   */

  /**
   * Creates a new instance with {@code null} as its detail message and no cause.
   *
   * @deprecated Prefer {@linkplain ExecutionError(Error)} a constructor that accepts a cause: Users
   *     of this class typically expect for instances to have a non-null cause. At the moment, you
   *     can <i>usually</i> still preserve behavior by passing an explicit {@code null} cause. Note,

        if (expression == null || expression.trim().isEmpty()) {
            return null;
        }

        try {
            return ReflectionValueExtractor.evaluate(expression, root, false);
        } catch (Exception e) {
            addFeedback("Failed to extract \'" + expression + "\' from: " + root, e);
        }

        return null;
    }

     * @param mavenProject the requested project
     * @return The projectSegment or null.
     */
    public ProjectSegment findByMavenProject(MavenProject mavenProject) {
        return items.stream()
                .filter(pb -> mavenProject.equals(pb.getProject()))
                .findFirst()
                .orElse(null);
    }

    @Override
    public Iterator<ProjectSegment> iterator() {

        return distributionName + " "
                + (version != null ? version : "<version unknown>")
                + (rev != null ? " (" + rev + ")" : "");
    }

    private static String reduce(String s) {
        return (s != null ? (s.startsWith("${") && s.endsWith("}") ? null : s) : null);
    }

    public static Properties getBuildProperties() {

      return;
    }

    map.put(null, unmappedValue);
    assertEquals(unmappedValue, map.get(null));
    assertTrue(map.containsKey(null));
    Entry<@Nullable K, V> entry = mapEntry(null, unmappedValue);
    assertTrue(entrySet.remove(entry));
    assertNull(map.get(null));
    assertFalse(map.containsKey(null));
  }

  public void testEntrySetRemoveNullKeyMissing() {

        } else if (upperBounds != null) {
            visitor.visitText("? extends ");
            upperBounds.visitSignature(visitor);
        } else if (lowerBounds != null) {
            visitor.visitText("? super ");
            lowerBounds.visitSignature(visitor);
        } else {
            visitor.visitType(name);
            if (typeArgs != null) {
                visitor.visitText("<");