code: public static void fatalError(Logger logger, Throwable t, String format, Object... args) {
      String message = String.format("Fatal error: " + format, args);
      if (t != null) {
        message += "\n" + ExceptionUtils.getStackTrace(t);
      }
      if (ServerConfiguration.getBoolean(PropertyKey.TEST_MODE)) {
        throw new RuntimeException(message);
      }
      logger.error(message);
      System.exit(-1);
    }
docs: Logs a fatal error and then exits the system.
  
  @param logger the logger to log to
  @param t the throwable causing the fatal error
  @param format the error message format string
  @param args args for the format string