private static List<String> screenUncRoots(List<String> roots, List<? super String> ignored) {
    List<String> filtered = null;
    for (int i = 0; i < roots.size(); i++) {
      String root = roots.get(i);
      if (OSAgnosticPathUtil.isUncPath(root)) {
        if (filtered == null) {
          filtered = new ArrayList<>(roots.subList(0, i));
        }
        ignored.add(root);
      }
      else if (filtered != null) {
        filtered.add(root);
      }
    }
    return filtered != null ? filtered : roots;
  }
private static List<String> screenUncRoots(List<String> roots, List<? super String> ignored)