* be read without locking. Next fields of nodes are immutable (final). All list additions are
     * performed at the front of each bin. This makes it easy to check changes, and also fast to
     * traverse. When nodes would otherwise be changed, new nodes are created to replace them. This

    return JavaLowerCase.INSTANCE;
  }

  /**
   * Determines whether a character is an ISO control character as specified by {@link
   * Character#isISOControl(char)}.
   *
   * <p>All ISO control codes are on the BMP and thus supported by this API.
   *
   * @since 19.0 (since 1.0 as constant {@code JAVA_ISO_CONTROL})
   */
  public static CharMatcher javaIsoControl() {
    return JavaIsoControl.INSTANCE;
  }

   * all are provided (an empty list), the resulting Cartesian product has one element, an empty
   * list (counter-intuitive, but mathematically consistent).
   *
   * <p><i>Performance notes:</i> while the cartesian product of sets of size {@code m, n, p} is a
   * set of size {@code m x n x p}, its actual memory consumption is much smaller. When the

        int[] codes = (int[]) propMap.get(CRAWLER_FAILURE_URL_STATUS_CODES);
        if (codes == null) {
            codes = split(getCrawlerFailureUrlStatusCodes(), ",")
                    .get(stream -> stream.filter(StringUtil::isNotBlank).mapToInt(Integer::parseInt).toArray());
            propMap.put(CRAWLER_FAILURE_URL_STATUS_CODES, codes);
        }
        for (final int v : codes) {

            // phase 1: get file Models from the reactor.
            List<InterimResult> interimResults = build(projectIndex, pomFiles, new LinkedHashSet<>(), true, recursive);

            ClassLoader oldContextClassLoader = Thread.currentThread().getContextClassLoader();

            try {
                // Phase 2: get effective models from the reactor

        succ = curr.next;
        if (curr.thread != null) { // we aren't unlinking this node, update pred.
          pred = curr;
        } else if (pred != null) { // We are unlinking this node and it has a predecessor.
          pred.next = succ;
          if (pred.thread == null) { // We raced with another node that unlinked pred. Restart.
            continue restart;
          }

        // effective model.
        //
        // As of 3.4, the model version is mandatory even in raw models. The XML element still is optional in the
        // XML schema and this will not change anytime soon. We do not want to build effective models based on
        // models without a version starting with 3.4.
        validateStringNotEmpty("modelVersion", problems, Severity.ERROR, Version.V20, m.getModelVersion(), m);