Java Socket Client-Server Chat Application

Overview

This project is a simple Java TCP socket-based client-server chat application.
It demonstrates how two Java programs (a server and a client) can communicate with each other in real time using:

• Socket and ServerSocket
• Multithreading
• Input/Output streams

Both the client and the server can send and receive messages simultaneously.

This project is useful for learning:

• Java networking fundamentals
• Blocking I/O
• Thread-based communication
• Basic real-time messaging concepts

this is medium blog which explains it all step by step : https://medium.com/nerd-for-tech/create-a-chat-app-with-java-sockets-8449fdaa933

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Technologies Used

• Java (Standard Edition)
• TCP Sockets (java.net)
• Multithreading (java.lang.Thread)
• I/O Streams (java.io)

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How It Works

Server

• Starts a ServerSocket on port 5000
• Waits for a client connection using accept()
• Creates two threads:
  • Sender Thread → Sends messages from server console to client
  • Receiver Thread → Receives messages from client and prints them

Client

• Connects to server at 127.0.0.1:5000
• Creates two threads:
  • Sender Thread → Sends messages from client console to server
  • Receiver Thread → Receives messages from server and prints them

This allows bi-directional communication at the same time.

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How to Run

Step 1 : Compile — Step 2 : Run server then client

javac Server.java
javac Client.java

java Server
java Client