please help
package com.codegym.task.task30.task3008;
import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Iterator;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
public class Server {
private static Map<String,Connection> connectionMap = new ConcurrentHashMap<>();
public static void main(String[] args) throws IOException {
int port = ConsoleHelper.readInt();
ServerSocket serverSocket = new ServerSocket(port);
System.out.println("Server is running");
try{
while(true) {
Socket socket = serverSocket.accept();
Handler handler = new Handler(socket);
handler.start();
}
}catch (IOException e){
e.printStackTrace();
serverSocket.close();
}
}
public static void sendBroadcastMessage(Message message){
Iterator<Map.Entry<String,Connection>> itr = connectionMap.entrySet().iterator();
while(itr.hasNext()){
Map.Entry<String,Connection> pair = itr.next();
Connection connection = pair.getValue();
String user = pair.getKey();
try{
connection.send(message);
}catch (IOException e){
System.out.println(user+" Message couldn't sent");
}
}
}
private static class Handler extends Thread{
private Socket socket;
public Handler(Socket socket){
this.socket = socket;
}
@Override
public void run() {
}
private String serverHandshake(Connection connection) throws IOException,ClassNotFoundException{
while(true) {
connection.send(new Message(MessageType.NAME_REQUEST));
Message response = connection.receive();
if (response.getType().equals(MessageType.USER_NAME)) {
String data = response.getData();
if (data != null) {
for (Map.Entry<String, Connection> pair : connectionMap.entrySet()) {
if ((data.equals(pair.getKey()))) {
}
}
connectionMap.put(data, connection);
connection.send(new Message(MessageType.NAME_ACCEPTED));
return data;
}
}
}
}
}
}