private static void doAllow(String... roots) {
    synchronized (ourAdditionalRoots) {
      for (String root : roots) {
        String path = StringUtil.trimEnd(FileUtil.toSystemIndependentName(root), '/');
        if (path.isEmpty()) {
          throw new IllegalArgumentException("Must not pass empty pat but got: '" + Arrays.toString(roots) + "'");
        }
        ourAdditionalRoots.add(path);
      }
    }
  }
private static void doAllow(String... roots)