this.element = element;
            this.sectionName = sectionName;
        }
    }

    /**
     * Fixes duplicate plugins in plugins and pluginManagement sections.
     */
    private boolean fixDuplicatePlugins(Document pomDocument, UpgradeContext context) {
        Element root = pomDocument.root();

        // Collect all build elements to process

  }

  /**
   * Adds the given element to this queue. If this queue has a maximum size, after adding {@code
   * element} the queue will automatically evict its greatest element (according to its comparator),
   * which may be {@code element} itself.
   *
   * @return {@code true} always
   */
  @CanIgnoreReturnValue
  @Override
  public boolean add(E element) {
    offer(element);
    return true;
  }

    }

    protected Element findChild(Element element, String childName) {
        NodeList childNodes = element.getChildNodes();
        for (int i = 0; i < childNodes.getLength(); i++) {
            Node node = childNodes.item(i);
            if (node instanceof Element) {
                Element childElement = (Element) node;

  // Query Operations

  /**
   * Returns the number of occurrences of {@code element} in this multiset.
   *
   * @param element the element to look for
   * @return the nonnegative number of occurrences of the element
   */
  @Override
  public int count(@Nullable Object element) {
    AtomicInteger existingCounter = safeGet(countMap, element);
    return (existingCounter == null) ? 0 : existingCounter.get();
  }

    if (occurrences == 0) {
      return count(element);
    }
    checkArgument(occurrences > 0, "occurrences cannot be negative: %s", occurrences);
    int entryIndex = backingMap.indexOf(element);
    if (entryIndex == -1) {
      backingMap.put(element, occurrences);
      size += occurrences;
      return 0;
    }
    int oldCount = backingMap.getValue(entryIndex);

        for (Element element : classDoc.getComment()) {
            parent.appendChild(document.importNode(element, true));
        }
        NodeList otherContent = classDoc.getClassSection().getChildNodes();
        for (int i = 0; i < otherContent.getLength(); i++) {
            Node child = otherContent.item(i);
            if (child instanceof Element && !((Element) child).getTagName().equals("section")) {

                for (PluginExecution element : tgt) {
                    Object key = getPluginExecutionKey(element);
                    merged.put(key, element);
                }

                for (PluginExecution element : src) {
                    Object key = getPluginExecutionKey(element);
                    PluginExecution existing = merged.get(key);

        final Entry entry = getEntry(index);
        final E oldValue = entry.element;
        entry.element = element;
        return oldValue;
    }

    /**
     * Returns the position of the element.
     *
     * @param element the element
     * @return the position
     */
    public int indexOf(final E element) {
        int index = 0;
        if (element == null) {

    final int hash;

    Element(int hash) {
      this.hash = hash;
    }

    @Override
    public boolean equals(@Nullable Object obj) {
      return this == obj || (obj instanceof Element && ((Element) obj).hash == hash);
    }

    @Override
    public int hashCode() {
      return hash;
    }

    @Override
    public int compareTo(Element that) {

  }

  @Override
  public boolean contains(@Nullable Object element) {
    return count(element) > 0;
  }

  // Modification Operations
  @CanIgnoreReturnValue
  @Override
  public final boolean add(@ParametricNullness E element) {
    add(element, 1);
    return true;
  }

  @CanIgnoreReturnValue
  @Override
  public int add(@ParametricNullness E element, int occurrences) {
    throw new UnsupportedOperationException();