private void checkVersion(int[] requiredVersion) throws IOException {
    if (m_registryVersion == null) {
      m_registryVersion = requiredVersion;
    }
    else if (requiredVersion != null) {
      for (int i = 0; i < requiredVersion.length; i++) {
        if (m_registryVersion[i] != requiredVersion[i]) {
          throw new RegistryFormatException("incorrect registry version no");
        }
      }
    }
  }