Question about page 488 of Head First Java

[Jose Campana]

Hiya! buddies. How's everything in the Ranch?
Have a nice happy and safe Halloween!
Leaving the ghostly matters aside I have a question concerning sockets and threads.
There's an exercise in the Head First book, it's about making a chat application, but in page 488 I don't understand the explanation given for not using Option number 2. It says:

Option Two: Read something in from the server each time the user sends a message.

--The book states that this option shouldn't be considered because it's an arbitrary time to check for messages.

Could someone explain me Why is it arbitrary? --because I would have done exactly as suggested in option 2.

And more Importantly,
I don't understand

Option 3: Read messages as soon as they're sent from the server

How exactly is option 3 different from Option 2?

I don't quite get it. *Help Me

I anticipate my most sincere gratitude for all you time.

Sincerely,
Jose

[Chris Corbyn]

I think the wording is perhaps a bit misleading. "User" refers to the local client I assume, and in which case if you only read from the server when the local client sends a message then you would only ever know if the remote client in the chat has said anything once you say something.

[Jose Campana]

Greetings...
Sorry, umMmMmM,

I'm still not gettin' it. What's wrong with me?

If someone could contribute to help me understand this little part, please let me know what you think.

Sincerely,
your friend, Jose

[Adam Schaible]

So option two says that I will retrieve everyone elses messages when I MYSELF send a message.

Option three says that I will retrieve everyone elses messages when THEY send a message.

Imagine if your IM client of choice didn't tell you what the person you're talking to said, until you sent them a message. It would be very difficult to have a conversation, and the reason it's arbitrary is because you may type a message every second, or every century.

[Jose Campana]

Hey Adam.!
Thank you very much... I've got it.
That's the clarification I just needed..

Keep on your excellent work ! You don't know how much I appreciate it ! But it's really a lot.

Thank you fellow java programmer.

Sincerely,
Jose