A Group Chat Application in Java

What is a group chat application?

A group chat application in Java is a piece of software that enables users to communicate with one another. Or we could say that a platform or a piece of software that enables users to chat with each other simultaneously is a group chat application. Users can participate in group discussions, share media files, and have real-time interactions thanks to it. Applications for group chat are often used for event planning, socialising with friends and family, and team collaboration.

Applications for group chat typically offer the following features:

• Users have the ability to create groups and invite others to join them.
• Users can communicate with the group by sending text messages, emojis, and stickers.
• Users can share documents, videos, photos, and other types of files.
• Users are notified when new messages or mentions are made.
• Users can manage group visibility and access through the privacy settings.
• Moderation: Administrators or the person who created the group may have additional controls to manage the group, such as the ability to add or remove members, manage permissions, or delete messages.
• Integration: To improve productivity and collaboration, some group chat applications integrate with other services like calendars, task management programmes, or file storage platforms.

For example:

Popular group chat software examples include:

• WhatsApp: A popular messaging service with end-to-end encryption, media sharing, and support for both private and public chats.
• Slack: A channel, direct message, and file-sharing communication and collaboration platform that is primarily made for team collaboration.
• Microsoft teams: Group chat, video conferencing, file sharing, and integration with other Microsoft products are all available through the comprehensive communication and collaboration platform known as Microsoft Teams.
• Telegram: Telegram is a cloud-based messaging service that includes channels, bots, group chats, and media sharing.
• Discord: Group chats, voice calls, and media sharing are available on Discord, a platform that was initially created for gamers but now supports a number of different communities.

These are just a few of the many group chat programmes that are available; each has a unique set of features and a different user base. The specific requirements and preferences of the users or group will determine which group chat application is best for them.

Development of a group chat application

The steps taken to create a Java group chat application:

1. The application's design: Find out the group chat application's general structure and features. Think about elements like data handling, communication protocol, and user interface.
2. Select a networking strategy: Choose your networking strategy to allow communication between the server and clients. Java offers a variety of options, including the use of ServerSocket and Socket classes for non-blocking I/O (NIO) or conventional socket programming.
3. Install the server: Create the server application first. The server should monitor incoming connections from clients and respond appropriately. To manage multiple clients at once, you can use multithreading or an event-driven methodology.
4. Execute the client: Create the client software. The client is responsible for connecting to the server and managing message sending and receiving. It ought to have a user interface for message input and display.
5. Define the protocol for communication: Establish the message format that the server and clients use when communicating. Details like message types, message fields (sender, timestamp, content), and any additional metadata should be included in this protocol.
6. Handle message broadcasting: Implement the logic to broadcast messages from one client to all connected clients in order to handle message broadcasting. Clients' messages should be forwarded to all other clients who are connected by the server after it receives them.
7. Manage user connections: if we want to manage the user connections then we need to build a data structure that will help to list all the user that are currently connected to the server, with the help of this we will be handle the user and help to send the message to clients.
8. Enhance functionality: Boost functionality by including extra features as needed, such as user authentication, private messaging, file sharing, or multimedia support. For secure communication, you might also take into account incorporating encryption.
9. Test and fix: Make sure the application is fully functional by giving it a thorough test run. Find any bugs or problems that surface during testing, and fix them. Be mindful of scenarios where multiple clients are active at once to guarantee proper synchronisation and message delivery.
10. Deploy and distribute: Package the server and client applications into executable or JAR files for distribution and deployment. Distribute the software to users or place it on servers that the target users can access.

Good software engineering practises, such as modularizing code, handling exceptions, and ensuring readability, must be adhered to at all times during the development process. To make activities like networking, UI design, and message serialisation simpler, take into consideration employing well-known tools or frameworks.

Requirement of group chat application

Depending on the particular demands and setting of the programme, different group chat applications may have different specifications. However, you might take into account the following typical requirements:

• User registration and identity verification: if we want to access the group chat then user should ne to sign or create an account and login through account to provide identification.
• With the ability for user to form a group we need a administer to add them or remove them from the group.
• Real-time messaging: Within the group chat, users should be able to send and receive messages instantly. Emojis, text, and multimedia items like files or photographs can all be included in messages.
• Users should be notified when there are new messages, mentions, or other pertinent activity in the group chat.
• A message history feature that enables users to view previous messages should be included in the programme. Additionally, users can use the chat history's search capability to locate particular messages.
• Multimedia sharing: if we want that within the group chat we can share the multimedia like picture, videos, document and links then we need to use multimedia sharing option in our software.
• User status and presence: The application needs to let users know if they are online or offline and whether they are present in the group chat.

You can further modify these specifications in accordance with your unique use case using these specifications as a starting point. To make sure the group chat application effectively satisfies their demands, it is crucial to involve stakeholders, collect their comments, and iterate on the requirements.

Source code

Server side

import java.io.*;
import java.net.*;
import java.util.*;
public class Server {
 private static Set<PrintWriter> clients = new HashSet<>();
 public static void main(String[] args) throws Exception {
 System.out.println("Server is running...");
 ServerSocket serverSocket = new ServerSocket(1234);
 while (true) {
 Socket clientSocket = serverSocket.accept();
 System.out.println("New client connected: " + clientSocket);
 PrintWriter out = new PrintWriter(clientSocket.getOutputStream(), true);
 clients.add(out);
 ClientHandler clientHandler = new ClientHandler(clientSocket, out);
 Thread clientThread = new Thread(clientHandler);
 clientThread.start();
 }
 }
 public static void broadcast(String message) {
 for (PrintWriter client : clients) {
 client.println(message);
 }
 }
}
class ClientHandler implements Runnable {
 private Socket clientSocket;
 private PrintWriter clientOut;
 public ClientHandler(Socket socket, PrintWriter out) {
 this.clientSocket = socket;
 this.clientOut = out;
 }
 @Override
 public void run() {
 try {
 BufferedReader in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
 String incomingMessage;
 while ((incomingMessage = in.readLine()) != null) {
 System.out.println("Received message: " + incomingMessage);
 Server.broadcast(incomingMessage);
 }
 // Client has disconnected
 System.out.println("Client disconnected: " + clientSocket);
 Server.clients.remove(clientOut);
 clientOut.close();
 in.close();
 clientSocket.close();
 } catch (IOException e) {
 e.printStackTrace();
 }
 }
}

Client side

import java.io.*;
import java.net.*;
import java.util.*;
public class Client {
 public static void main(String[] args) throws Exception {
 Socket clientSocket = new Socket("localhost", 1234);
 System.out.println("Connected to the server.");
 BufferedReader in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
 PrintWriter out = new PrintWriter(clientSocket.getOutputStream(), true);
 Thread readThread = new Thread(new ReadHandler(in));
 readThread.start();
 Scanner scanner = new Scanner(System.in);
 String message;
 while ((message = scanner.nextLine()) != null) {
 out.println(message);
 }
 // Close the resources
 out.close();
 in.close();
 clientSocket.close();
 }
}
class ReadHandler implements Runnable {
 private BufferedReader serverIn;
 public ReadHandler(BufferedReader in) {
 this.serverIn = in;
 }
 @Override
 public void run() {
 try {
 String incomingMessage;
 while ((incomingMessage = serverIn.readLine()) != null) {
 System.out.println("Received: " + incomingMessage);
 }
 } catch (IOException e) {
 e.printStackTrace();
 }
 }
}

In the above example we created a simple server that will accept clients connections and after receiving it will broadcasts message from one client to all the other clients that are connected to the server. This client application will help to establish a connection with the server and enables the user to broadcast message to the other clients who are also connected.