return treeRoot == null ? null : new MetadataGraph(treeRoot);
    }
    // ----------------------------------------------------------------------------
    public MetadataGraph getGraph(ArtifactScopeEnum scope)
            throws MetadataResolutionException, GraphConflictResolutionException {
        if (treeRoot == null) {
            return null;
        }

        if (conflictResolver == null) {

     * StringUtil.defaultString("aaa", "NULL") = "aaa"
     * StringUtil.defaultString("aaa", null)   = "aaa"
     * StringUtil.defaultString(null, null)    = null
     * </pre>
     *
     * @param str
     *            the string (can be <code>null</code>)
     * @param defaultStr
     *            the string to return if the argument is <code>null</code> (can be <code>null</code>)

    assertFalse(entries.contains(Maps.<String, @Nullable Boolean>immutableEntry("c", null)));
    assertFalse(entries.contains(Maps.<@Nullable String, Boolean>immutableEntry(null, true)));
  }

  @Override
  public void testKeySetRemoveAllNullFromEmpty() {
    try {
      super.testKeySetRemoveAllNullFromEmpty();
    } catch (RuntimeException tolerated) {

     *
     * @param child The child model, must not be <code>null</code>.
     * @param parent The parent model, may be <code>null</code>.
     * @param childDirectory The directory defined in child model, may be <code>null</code>.
     * @return The path adjustment, can be empty but never <code>null</code>.
     */
    private String getChildPathAdjustment(Model child, Model parent, String childDirectory) {

        this.groupId = (groupId != null && !groupId.isEmpty()) ? groupId : null;
        this.artifactId = (artifactId != null && !artifactId.isEmpty()) ? artifactId : null;
        this.classifier = (classifier != null && !classifier.isEmpty()) ? classifier : null;
        this.extension = (extension != null && !extension.isEmpty()) ? extension : null;

  type: KClass<T>,
  compute: () -> T,
): T {
  var computed: T? = null

  while (true) {
    val tags = get()

    // If the element is already present. Return it.
    val existing = tags[type]
    if (existing != null) return existing

    if (computed == null) {
      computed = compute()
    }

    // If we successfully add the computed element, we're done.

        current.elemCount = 0;
        // Also clear these fields so that one deleted Entry doesn't retain all elements.
        current.left = null;
        current.right = null;
        current.pred = null;
        current.succ = null;

        current = next;
      }
      successor(header, header);
      rootReference.clear();
    } else {

    MEMBER_ID INTEGER IDENTITY NOT NULL PRIMARY KEY,
    MEMBER_NAME VARCHAR(200) NOT NULL,
    MEMBER_ACCOUNT VARCHAR(50) NOT NULL,
    MEMBER_STATUS_CODE CHAR(3) NOT NULL,
    FORMALIZED_DATETIME DATETIME,
    BIRTHDATE DATE,
    REGISTER_DATETIME DATETIME NOT NULL,
    REGISTER_USER VARCHAR(200) NOT NULL,
    UPDATE_DATETIME DATETIME NOT NULL,
    UPDATE_USER VARCHAR(200) NOT NULL,
    VERSION_NO BIGINT NOT NULL

     *   <li>Ensures no null repository entries exist in the list</li>
     * </ul>
     *
     * <p>Duplicate detection is based on the {@code RemoteRepository#equals(Object)}
     * method, which typically compares repository IDs and URLs.
     *
     * @param repositories the list of repositories to validate, may be {@code null}
     * @return the same list if validation passes, or {@code null} if input was {@code null}

   *
   * @return {@code first} if it is non-null; otherwise {@code second} if it is non-null
   * @throws NullPointerException if both {@code first} and {@code second} are null
   * @since 18.0 (since 3.0 as {@code Objects.firstNonNull}).
   */
  public static <T> T firstNonNull(@Nullable T first, @Nullable T second) {
    if (first != null) {
      return first;
    }
    if (second != null) {
      return second;
    }