OOP - Statuses (ServerSide)

package f2015.ex3;

import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.HashMap;
import java.util.Map;

public class Server {
    public static void main(String[] args) {
        try {
            Map<String, String> mp = new HashMap<>();
            ServerSocket ss = new ServerSocket(8080);
            while (true) {
                Socket s = ss.accept();
                System.out.println("New Connection!");
                new worker(s, mp).start();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }


    private static class worker extends Thread {
        private PrintWriter pw;
        private BufferedReader br;
        private Map<String, String> mp;

        worker(Socket s, Map<String, String> mp) {
            try {
                InputStream is = s.getInputStream();
                InputStreamReader isr = new InputStreamReader(is);
                br = new BufferedReader(isr);

                OutputStream os = s.getOutputStream();
                pw = new PrintWriter(os, true);
                this.mp = mp;
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        public void run() {
            while (true) {
                try {
                    String line = br.readLine();
                    System.out.println("New Request : " + line);
                    if (line.contains(":"))
                        change_status(line);
                    else
                        send_status(line);
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }

        private void change_status(String line) {
            int ind = line.indexOf(":");
            String name = line.substring(0, ind);
            String status = line.substring(ind + 1);
            synchronized (mp) {
                mp.put(name, status);
            }
        }

        private void send_status(String line) {
            String status;
            synchronized (mp) {
                status = mp.get(line);
            }
            this.pw.println(status);
        }
    }
}