— Scott McNealy, Sun Microsystems Chairman, President and ceo

participants’ messages, you get to load and 
play a beat pattern simply by clicking the 
message in the incoming messages area.
In this chapter we’re going to learn what it 
takes to make a chat client like this. We’re 
even going to learn a little about making a 
chat server. We’ll save the full Beat Box Chat 
for the Code Kitchen, but in this chapter you 
will write a Ludicrously Simple Chat Client and 
Very Simple Chat Server that send and receive 
text messages.
clicking on a received message 
loads the pattern that went 
with it
Type a message and 
press the sendIt 
button 
to send your message 
AND your current 
beat 
pattern
You can have completely 
authentic, intellectually 
stimulating chat 
conversations. Every 
message is sent to all 
participants.
Send your message to the server

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networking 
and
threads
you are here
4
473
Why am I 
here? Don’t 
expect ME to 
answer that.
Why am I 
here? Don’t 
expect ME to 
answer that.
Why am I 
here? Don’t 
expect ME to 
answer that.
The Client has to know 
about the Server.
The Server has to know 
about ALL the Clients.
Chat Program Overview
1
Client connects to the server
2
The server makes a 
connection and adds the client 
to the list of participants
3
Another client connects
4
Client A sends a message to 
the chat service
Client A
Client B
Client C
Server
there are currently 
3 participants in 
this chat session: 
Client A, Client B 
and Client C