class LazySecretKeyImpl implements LazySecretKey {

    @Override
    public @Nullable SecretKey getExisting() throws Exception {
        synchronized (lock) {
            if (secretKey == null) {
                File secretFile = getSecretFile(confDirs);
                if (secretFile != null) {
                    secretKey = loadKey(secretFile);
                }
            }
            return secretKey;
        }
    }

      LazySecretKeyImpl(List<File> confDirs);

}