thread on server will stop and I have no idea why

i am making a client handler for my chat app so I can have more then one client connected but right it just 2 connections and the 2 connections run on 2 threads(1 client per thread) now everything work fine and the server will get info from both client but after a while (1 sec) which every client will talk with the last will stay connected and the server stops the other thread running the other connection and I have no idea why

Server code

import java.io.IOException;
import java.net.ServerSocket;


public class server{
   
    public static ServerSocket serverSocket;
    public static void main(String[] args)throws IOException{
    serverSocket = new ServerSocket(1234);        
    clientHandler clientHandler = new clientHandler();
    Thread clienThread = new Thread(clientHandler);
    Thread clienThread2 = new Thread(clientHandler);
    clienThread.start();
    clienThread2.start();
    }
}

client Handler code

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;

public class clientHandler implements Runnable{
    public static server server = new server();
    public static Socket socket;
    public static BufferedReader in;
    public static PrintWriter out;

    @Override
    public void run(){
    try {
    socket = server.serverSocket.accept();
    in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
    out = new PrintWriter(socket.getOutputStream(), true);
    while(true){
        String msg = in.readLine();
        System.out.println(msg);
    }
        } catch (IOException ex) {
            ex.printStackTrace();
        }
    }
}

I tried to use 2 server sockets on 2 different port but got the same problem so please help

Usually, you create a single ServerSocket and a loop where

• the server waits for a client to connect
• a client connects
• create your client class, passing it the socket that just connected
• server goes back to waiting
• client handles the new socket io in a separate thread

You have two threads and each thread calls socket = server.serverSocket.accept(); I'm not sure how that works but I don't recommend it.

I've modified your code with as few changes as I could so you can follow it:

import java.io.IOException;
import java.io.BufferedReader;
import java.io.PrintWriter;
import java.io.InputStreamReader;
import java.net.ServerSocket;
import java.net.Socket;

public class Server
{
    public static class ClientHandler implements Runnable
    {
        private Socket socket;
        private Thread thread;
        
        public ClientHandler(Socket socket) {
            this.socket = socket;
            thread = new Thread(this);
            thread.start();
        }

        @Override
        public void run() {
            try {
                BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
                PrintWriter out = new PrintWriter(socket.getOutputStream(), true);
                String msg;
                while ((msg = in.readLine()) != null) {
                    System.out.println(msg);
                    out.println(msg);
                }
            }
            catch (IOException ex) {
                ex.printStackTrace();
            }
        }
    }

    public static void main(String[] args)throws IOException {
        ServerSocket serverSocket = new ServerSocket(1234);
        while (true) {
            Socket socket = serverSocket.accept();
            ClientHandler clientHandler = new ClientHandler(socket);
        }
    }
}

Note: this allows an "infinite" number of clients to connect. If you want to cap it at 2, you'll need to add a little extra logic.