import java.io.*;
import java.net.*;
public class TCPServer
{
    public static void main(String argv[]) throws Exception
    {
        ServerSocket welcomeSocket = new ServerSocket(3001);
        while(true)
        {
            Socket connectionSocket = welcomeSocket.accept();
            new Thread(new TCPServer(). new Client(connectionSocket)).start();
        }
    }
    public class Client implements Runnable{
        Socket client;
        String clientSentence;
        String capitalizedSentence;
        public Client(Socket s){
            client = s;
        }
        @Override
        public void run(){
            try{
                BufferedReader inFromClient =
                new BufferedReader(new InputStreamReader(client.getInputStream()));
                DataOutputStream outToClient = new DataOutputStream(client.getOutputStream());

        while((clientSentence = inFromClient.readLine())!=null){
                    System.out.println("Received: " + clientSentence);
                    capitalizedSentence = clientSentence.toUpperCase() + '\n';
                    outToClient.writeBytes(capitalizedSentence);
                }
            }catch(Exception e){e.printStackTrace();}
        }
    }
}