code: static void validateStartupOptions(StartupInfo startInfo) throws IOException {
      // sync cannot be specified along with format or finalize
      if (startInfo.isStandby) {
        if (startInfo.startOpt == StartupOption.FORMAT ||
            startInfo.startOpt == StartupOption.FINALIZE ||
            startInfo.startOpt == StartupOption.ROLLBACK ||
            startInfo.startOpt == StartupOption.UPGRADE) {
          throw new IOException("Standby avatar node cannot be started with " +
            startInfo.startOpt + " option.");
        }
      }
    }
docs: validates command line arguments