The document describes a chat server application built using Java sockets. It includes a client and server component that allow users to login and send messages to each other. The server uses multithreading to handle multiple client connections concurrently by passing accepted socket connections to separate thread objects. The chat server provides group and private messaging capabilities and could be expanded in the future to include additional features like offline messaging, file sharing, and a user profile database.

1. CHAT SERVER BASED ON JAVA
Under the guidance of:
Mrs. Jaya Sharma,
Dept. of CS&E,
ASET.
Submitted by-
Nitish Nagar (A2305208383)
Rajkumar Mahalawat(A2305208440)
Raman Sethi (A2305208416)
B.Tech(CS&E) : 2008-12
Semester : 5th

2. CHAT SERVER
 The “Chat Server” is a windows-based internet
chatting software system.
 It is composed of two major subsystems: a Server
and a Client, which are independent processes that
can be executed on separate computers on a
network.
 This includes allowing clients to login so they can be
identified by username and forwarding messages
from one client destined to another.
 Examples of Chatting Applications : Gtalk, Yahoo
Messenger,Hotmail.
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3. SOCKETS AND JAVA SOCKET CLASSES
 A socket is an endpoint of a two-way communication link
between two programs running on the network.
 A socket is bound to a port number so that the TCP
layer can identify the application that data destined to be
sent.
 Java’s .net package provides two classes:
Socket – for implementing a client
ServerSocket – for implementing a server
 There are four fundamental operations a socket
performs. These are:
Connect to a remote machine
Send data
Receive data
Close the connection
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4. …
 Sockets provide an interface for programming
networks at the transport layer.
 A socket is a reliable connection for the transmission
of data between two hosts.
 A server (program) runs on a specific computer and
has a socket that is bound to a specific port. The
server waits and listens to the socket for a client to
make a connection request.
 Socket-based communication is programming
language independent.
That means, a socket program written in Java language can
also communicate to a program written in Java or non-Java
socket program.
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5. CLIENT SERVER PROGRAMMING
 Client/server describes the relationship between two
computer programs in which one program, the client,
makes a service request from another program, the
server, which fulfills the request.
 Clients and servers are connected by sockets.
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Server- waits
Client- sends a for requests
request
Server- returns
a replay
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6. CLIENT/SERVER SOCKET INTERACTION:
TCP
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Server (running on hostid) Client
create socket,
port=x, for
incoming request:
welcomeSocket =
ServerSocket()
wait for incoming
connection request
connectionSocket =
welcomeSocket.accept()
create socket,
connect to hostid, port=x
clientSocket =
Socket()
read request from clientSocket
connectionSocket
close
connectionSocket
send request using
read reply from
connectionSocket
close
clientSocket
write reply to
connectionSocket
TCP
connection setup
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7. SOCKET PROGRAMMING WITH TCP
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Client must contact server
 server process must first
be running
 server must have created
socket (door) that
welcomes client’s contact
Client contacts server by:
 creating client-local TCP
socket
 specifying IP address, port
number of server process
 When client creates socket:
client TCP establishes
connection to server TCP
 When contacted by client,
server TCP creates new
socket for server process to
communicate with client
allows server to talk with
multiple clients
application viewpoint
TCP provides reliable, in-order
transfer of bytes (“pipe”)
between client and server
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8. Client Programming Server Programming
 Basic steps
1. Determine server
location – IP address
& port
2. Open network
connection to server
3. Write data to server
(request)
4. Read data from
server (response)
5. Close network
connection
6. Stop client
 Basic steps
1. Determine server
location - port (& IP
address)
2. Create server to listen
for connections
3. Open network
connection to client
4. Read data from client
(request)
5. Write data to client
(response)
6. Close network
connection to client
7. Stop server
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9. THREADING
 No more than one server socket can listen to a
particular port at one time.
 Since a server may need to handle many
connections at once, server programs tend to be
heavily multi-threaded.
 Generally the server socket passes off the actual
processing of connections to a separate thread.
 There should be a loop which continually accepts
new connections.
 Rather than handling the connection directly the
socket should be passed to a Thread object that
handles the connection.
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10. MULTITHREADED SERVER: FOR
SERVING MULTIPLE CLIENTS
CONCURRENTLY
Client 1 Process Server Process
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Server
Threads
Client 2 Process
Internet
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13. APPLICATION
 This also includes listing the usernames of the
clients that are currently logged in to facilitate
communication.
 A “Chat Server” is a form of real-time Internet text
messaging (chat) or synchronous conferencing.
 It is mainly designed for group communication in
discussion forums, called channels, but also
allows one-to-one communication via private
message as well as chat and data transfers
via Direct Client-to-Client.
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14. FUTUTRE SCOPE
 Login session information: We can include a feature
in this application that will keep a record of the user’s
login session.
 Offline messages: User can send messages to friends
even when they are offline.
 File transferring and sharing: User can transfer one or
more files to other users. A file can also be shared
between two or more users.
 Profile Database: The profile information of every user
can be stored at the server.
 Login Timeout: This feature allows the user to be
logged in only for a specific time. After this time span
ends, the user is automatically logged out
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15. THANK YOU