code: public static void main(String[] args) {
      validateArguments(args);
  
      EchoClient echoClient = newEchoClient(lenientParsePort(args[0]));
  
      for (int index = 1; index < args.length; index++) {
        System.out.println(echoClient.sendMessage(args[index]));
      }
    }
docs: Main method used to run the {@link EchoClient} program.
  
  @param args array of {@link String arguments} passed into this program from the command-line.
  @see #validateArguments(String[])
  @see #newEchoClient(int)
  @see #sendMessage(String)