diff --git a/src/main/java/com/university/chat/Server/ClientSession.java b/src/main/java/com/university/chat/Server/ClientSession.java
index f09d64a..1f66a14 100644
--- a/src/main/java/com/university/chat/Server/ClientSession.java
+++ b/src/main/java/com/university/chat/Server/ClientSession.java
@@ -2,44 +2,80 @@ package com.university.chat.Server;
 
 import com.university.chat.Common.ChatMessage;
 import com.university.chat.Common.FileMessage;
+import com.university.chat.Common.MessageType;
 
 import java.io.IOException;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
 import java.net.Socket;
 import java.nio.file.Files;
 
 public class ClientSession implements Runnable {
 
     private String username;
+    private final UserManager userManager;
+    private final Socket socket;
+    private ObjectOutputStream out;
+    private ObjectInputStream in;
 
     public ClientSession(Socket socket, UserManager userManager) {
-        // TODO : Create an ObjectOutputStream from socket.getOutputStream()
-        //         and an ObjectInputStream from socket.getInputStream().
+        this.socket = socket;
+        this.userManager = userManager;
+        try {
+            out = new ObjectOutputStream(socket.getOutputStream());
+        } catch (IOException e) {
+            System.out.println(e.getMessage());
+        }
+
+        try {
+            in = new ObjectInputStream(socket.getInputStream());
+        } catch (IOException e) {
+            System.out.println(e.getMessage());
+        }
     }
 
     @Override
     public void run() {
         try {
+            System.out.println("Welcome");
+            boolean isLogedIn = false;
+            Object firstObject = in.readObject();
+            if(firstObject instanceof ChatMessage){
+                isLogedIn = ((ChatMessage)firstObject).getType() == MessageType.LOGIN;
+            }
 
-            // TODO: Welcome the user (login step)
-            //  1. Read the first object sent by the client.
-            //  2. Check it's a ChatMessage with type LOGIN.
-            //  3. Extract the username.
-            //  4. Try to register the user via userManager.addUser(...).
-            //  5. If the username is taken, send back LOGIN_FAILED and close the socket.
-            //  6. Otherwise, create the user's folders with FileManager.createUserFolders(...)
-            //      and send back LOGIN_SUCCESS.
+            if(!isLogedIn){
+                socket.close();
+                return;
+            }
 
-            // TODO: Main message loop
-            //   In a loop, call in.readObject(), you can separate messages by their type:
-            //     - if it's a ChatMessage      -> call handleChatMessage(msg)
-            //     - if it's a FileMessage      -> call handleFileMessage(fileMsg)
-            //   Keep looping until the connection is closed (an exception will be thrown).
+            username = ((ChatMessage) firstObject).getSender();
+            if(userManager.addUser(username, this)){
+                System.out.println(username + " user name added.");
+                FileManager.createUserFolders(username);
+                out.writeObject(MessageType.LOGIN_SUCCESS);
+                out.flush();
+            }
+            else{
+                System.out.println("try another username.");
+                out.writeObject(MessageType.LOGIN_FAILED);
+                out.flush();
+                socket.close();
+                return;
+            }
+
+            while(true){
+                Object obj = in.readObject();
+                if(obj instanceof ChatMessage)
+                    handleChatMessage((ChatMessage) obj);
+                else if(obj instanceof FileMessage)
+                    handleFileMessage((FileMessage) obj);
+            }
 
         } catch (Exception e) {
             System.out.println("Disconnected: " + username);
         } finally {
-            // TODO: Remove the user from UserManager so they no longer
-            //        receive broadcasts or appear in users list
+            userManager.removeUser(username);
         }
     }
 
@@ -47,13 +83,32 @@ public class ClientSession implements Runnable {
     private void handleChatMessage(ChatMessage msg) throws IOException {
         switch (msg.getType()) {
             case PUBLIC_MESSAGE -> {
-                // TODO: Broadcast this message to every connected client.
+                Iterable<ClientSession> users = userManager.getAllSessions();
+                for(ClientSession user : users){
+                    user.send(msg);
+                }
             }
             case PRIVATE_MESSAGE -> {
-                // TODO: Forward this message to the receiver user.
+                ClientSession receiver = userManager.getUser(msg.getReceiver());
+                if(receiver != null){
+                    receiver.send(msg);
+                }
+                else{
+                    send(new ChatMessage(
+                            MessageType.PRIVATE_MESSAGE,
+                            "server",
+                            username,
+                            "User doesn't exist: " + msg.getReceiver()
+                    ));
+                }
             }
             case USER_LIST -> {
-                // TODO: Reply to the requester with the list of online users.
+                send(new ChatMessage(
+                        MessageType.USER_LIST,
+                        "server",
+                        username,
+                        userManager.listUsers()
+                ));
             }
         }
     }
@@ -66,6 +121,11 @@ public class ClientSession implements Runnable {
         Files.write(sentPath, fileMsg.getData());
         Files.write(recvPath, fileMsg.getData());
 
-        // TODO: Forward the received file-message to the destination user.
+        ClientSession receiver = userManager.getUser(fileMsg.getReceiver());
+        receiver.send(fileMsg);
+    }
+    private synchronized void send(Object obj) throws IOException{
+        out.writeObject(obj);
+        out.flush();
     }
 }
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