我的java聊天服务器程序不会向连接的每个用户广播

import java.io.IOException;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class ChatServer {
    private List<PrintWriter> clientWriters;

    public ChatServer() {
        clientWriters = new ArrayList<>();
    }

    public void start(int port) {
        try {
            ServerSocket serverSocket = new ServerSocket(port);
            System.out.println("Chat server started on port " + port);

            while (true) {
                Socket clientSocket = serverSocket.accept();
                System.out.println("New client connected: " + clientSocket);

                PrintWriter writer = new PrintWriter(clientSocket.getOutputStream(), true);
                clientWriters.add(writer);

                Thread clientThread = new Thread(new ClientHandler(clientSocket));
                clientThread.start();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private void broadcast(String message) {
        for (PrintWriter writer : clientWriters) {
            writer.println(message);
        }
    }

    private class ClientHandler implements Runnable {
        private Socket clientSocket;
        private Scanner scanner;

        public ClientHandler(Socket clientSocket) {
            this.clientSocket = clientSocket;
        }

        @Override
        public void run() {
            try {
                scanner = new Scanner(clientSocket.getInputStream());

                while (scanner.hasNextLine()) {
                    String message = scanner.nextLine();
                    System.out.println("Received message: " + message);
                    broadcast(message);
                }
            } catch (IOException e) {
                e.printStackTrace();
            } finally {
                scanner.close();
                clientWriters.remove(new PrintWriter(clientSocket.getOutputStream(), true));
                System.out.println("Client disconnected: " + clientSocket);
            }
        }
    }

    public static void main(String[] args) {
        ChatServer server = new ChatServer();
        server.start(8080);
    }
}