Index, added simple code for connection.

src/main/java/ChatServer.java

@@ -0,0 +1,84 @@
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.io.PrintWriter;
+import java.net.ServerSocket;
+import java.net.Socket;
+import java.util.ArrayList;
+
+
+public class ChatServer implements Runnable {
+    private int port = 9000;
+    private ArrayList<Socket> clientSockets = new ArrayList<Socket>();
+
+    public ChatServer() {
+    }
+
+    public ChatServer(int port) {
+        this.port = port;
+    }
+
+    private User getOrCreateUser(String username) {
+        return new User(username);
+    }
+
+    private void SendMessage(User user, String msg) {
+        try {
+            for (Socket client : clientSockets) {
+                PrintWriter out = new PrintWriter(client.getOutputStream(), true);
+
+                out.println(user.getUsername() + " " + msg);
+            }
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+    }
+
+    private void handleClient(Socket socket) {
+        try {
+            clientSockets.add(socket);
+
+            String msg;
+            User user = null;
+
+            PrintWriter out = new PrintWriter(socket.getOutputStream(), true);
+            BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
+
+            out.println("Login: /login username");
+            while ((msg = in.readLine()) != null) {
+                if (user != null) {
+                    SendMessage(user, msg);
+                }
+
+                if (user == null) {
+                    if (msg.toLowerCase().startsWith("/login")) {
+                        String username = msg.substring(6).strip();
+                        user = getOrCreateUser(username);
+                    }
+                }
+            }
+
+        } catch (IOException e) {
+            clientSockets.remove(socket);
+            e.printStackTrace();
+        }
+    }
+
+
+    @Override
+    public void run() {
+        try {
+            ServerSocket serverSocket = new ServerSocket(port);
+
+            while (true) {
+                Socket clientSocket = serverSocket.accept();
+
+                Thread thread = new Thread(() -> handleClient(clientSocket));
+                thread.start();
+            }
+
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+    }
+}

src/main/java/Client.java

@@ -0,0 +1,62 @@
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.io.PrintWriter;
+import java.net.Socket;
+import java.util.Scanner;
+
+public class Client {
+    private Socket clientSocket;
+    private PrintWriter out;
+    private BufferedReader in;
+
+    public void startConnection(String ip, int port) throws IOException {
+        clientSocket = new Socket(ip, port);
+        out = new PrintWriter(clientSocket.getOutputStream(), true);
+        in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
+    }
+
+    public void sendMessage(String message) throws IOException {
+        out.println(message);
+    }
+
+    public String loadMessage() throws IOException {
+        String resp = in.readLine();
+        return resp;
+    }
+
+    public void stopConnection() throws IOException {
+        in.close();
+        out.close();
+        clientSocket.close();
+    }
+
+    public static void main(String[] args) throws IOException {
+        Client client = new Client();
+        client.startConnection("127.0.0.1", 9000);
+
+        String msg;
+        Scanner scanner = new Scanner(System.in);
+
+        Thread thread = new Thread(() -> {
+            try {
+                String resp;
+
+                while (true) {
+                    resp = client.loadMessage();
+                    System.out.println(resp);
+                }
+            } catch (IOException e) {
+                throw new RuntimeException(e);
+            }
+        });
+        thread.start();
+
+        while (true) {
+            msg = scanner.nextLine();
+            client.sendMessage(msg);
+        }
+
+//        client.stopConnection();
+    }
+}

src/main/java/Main.java

@@ -0,0 +1,10 @@
+public class Main {
+    public static void main(String[] args) {
+        ChatServer chatServer = new ChatServer(9000);
+
+
+        Thread serverThread = new Thread(chatServer);
+        serverThread.start();
+
+    }
+}

src/main/java/User.java

@@ -0,0 +1,16 @@
+public class User {
+
+    private String username;
+
+    public User(String username) {
+        this.username = username;
+    }
+
+    public String getUsername() {
+        return username;
+    }
+
+    public void setUsername(String username) {
+        this.username = username;
+    }
+}