ex1

.gitignore

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+bin
+lib
+.vscode

README.md

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+## Getting Started
+
+Welcome to the VS Code Java world. Here is a guideline to help you get started to write Java code in Visual Studio Code.
+
+## Folder Structure
+
+The workspace contains two folders by default, where:
+
+- `src`: the folder to maintain sources
+- `lib`: the folder to maintain dependencies
+
+Meanwhile, the compiled output files will be generated in the `bin` folder by default.
+
+> If you want to customize the folder structure, open `.vscode/settings.json` and update the related settings there.
+
+## Dependency Management
+
+The `JAVA PROJECTS` view allows you to manage your dependencies. More details can be found [here](https://github.com/microsoft/vscode-java-dependency#manage-dependencies).

src/Ex1/App.java

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+package Ex1;
+
+import java.net.InetSocketAddress;
+
+public class App {
+    public static void main(String[] args) throws Exception {
+        Server server = new Server(6666);
+        Client client = new Client(new InetSocketAddress("localhost", 6666));
+        Client client2 = new Client(new InetSocketAddress("localhost", 6666));
+    }
+}

src/Ex1/Client.java

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+package Ex1;
+
+import java.io.IOException;
+import java.net.DatagramPacket;
+import java.net.DatagramSocket;
+import java.net.InetSocketAddress;
+import java.util.Random;
+import java.util.Scanner;
+
+public class Client {
+
+	private final DatagramSocket socket;
+	private final InetSocketAddress address;
+
+	/**
+	 * Create a new client
+	 * 
+	 * @param address server adress (needed
+	 * @throws IOException
+	 */
+	public Client(InetSocketAddress address) throws IOException {
+		this.address = address;
+		this.socket = new DatagramSocket();
+		sendGreetings();
+		readMessage();
+		this.socket.close();
+	}
+
+	private void sendGreetings() throws IOException {
+		sendMessage("Bonjour, je suis un client");
+	}
+
+	public void sendMessage(String message) throws IOException {
+		byte[] buffer = message.getBytes();
+		DatagramPacket packet = new DatagramPacket(buffer, buffer.length, this.address.getAddress(),
+				this.address.getPort());
+		this.socket.send(packet);
+	}
+
+	private void processMessage(DatagramPacket packet) {
+		String message = new String(packet.getData(), 0, packet.getLength());
+		System.out.println("[Client] Message recieved : " + message);
+	}
+
+	private boolean readMessage() {
+		byte[] buffer = new byte[1024];
+		DatagramPacket packet = new DatagramPacket(buffer, buffer.length);
+		try {
+			this.socket.receive(packet);
+			processMessage(packet);
+		} catch (IOException e) {
+			e.printStackTrace();
+			return false;
+		}
+		return true;
+	}
+
+	private void readMessages() {
+		while (true) {
+			if(!readMessage())
+				break;
+		}
+	}
+
+}

src/Ex1/Server.java

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+package Ex1;
+
+import java.io.IOException;
+import java.net.DatagramPacket;
+import java.net.DatagramSocket;
+import java.net.InetAddress;
+import java.net.SocketException;
+import java.time.Instant;
+
+public class Server {
+
+	private final DatagramSocket socket;
+
+	public Server(int port) throws SocketException {
+		this.socket = new DatagramSocket(port);
+		new Thread(this::readMessages).start();
+	}
+
+	public int getPort() {
+		return this.socket.getLocalPort();
+	}
+
+	private void sendMessage(String message, InetAddress address, int port) throws IOException {
+		byte[] buffer = message.getBytes();
+		DatagramPacket packet = new DatagramPacket(buffer, buffer.length, address, port);
+		this.socket.send(packet);
+	}
+
+	private void processMessage(DatagramPacket packet) throws IOException {
+		String message = new String(packet.getData(), 0, packet.getLength());
+		System.out.println("[Server] Message recieved : " + message);
+		sendMessage("Bonjour, il est " + Instant.now(), packet.getAddress(), packet.getPort());
+	}
+
+	private void readMessages() {
+		while (true) {
+			byte[] buffer = new byte[1024];
+			DatagramPacket packet = new DatagramPacket(buffer, buffer.length);
+			try {
+				this.socket.receive(packet);
+				processMessage(packet);
+			} catch (IOException e) {
+				e.printStackTrace();
+				break;
+			}
+		}
+	}
+
+}