The Programming Bot

GUI Chat Application in Java using Sockets : The First Part

Java Socket Programming is used to establish the connection between the application running on different JREs, and Java Sockets are the end-points of that communication. In the client-server based architecture, the two end-points are Client and Server. Client is represented by Socket class and Server is represented by ServerSocket class of Java situated in java.net package.

Client and Server have their input and output streams. We access those streams and make the client and server communicate with each other.

We have divided the task of building GUI Chat App in following steps:

• 1. Create the Server
• 2. Create GUI Client
• 3. Associate client with ClientHandler
• 4. Communication among multiple instances of Clients

We will cover them in series of blog posts.

1. Create the Server

We create a Server class which :

• i) has ServerSocket and a port
• ii) listens clients' requests
• iii) responses to the clients

We implement this in code as :

Test it With Telnet Client

Open your terminal and open a telnet session to request to the server at localhost listening to the port 6000.

Up to now, we got our server running which accept the clients' requests and send them the message "Hello Client".

But, there is a little problem here. The problem is that the Server class is assigned with two responsibilites, first is handling clients and second is starting the problem as it has main method. This, kind of, violates SOLID principle. So, we need to refactor this class. We will do it in subsequent post.