private static @Nullable String findWaitingForLock(final String stackTrace) {
    Matcher m = ourWaitingForLockPattern.matcher(stackTrace);
    if (m.find()) {
      return m.group(2);
    }
    m = ourParkingToWaitForLockPattern.matcher(stackTrace);
    if (m.find()) {
      return m.group(1);
    }
    return null;
  }
private static @Nullable String findWaitingForLock(final String stackTrace)