Bad publish() / process() interaction in Java Swing

Question

I'm programming an online videogame in java. I've already done the server and now I'm onto the client. My problem lies somewhere in the socket listener code, a swingworker subclass whose job is to listen to the server (doInBackGround()) and update the game map as necessary.

Here's the code:

import javax.swing.*;
import java.util.List;

public class GameWorker extends SwingWorker<Void, String> {

    private SocketStreamsBean streams;
    private GameFrame game;

    public GameWorker(SocketStreamsBean streams, GameFrame game) {
        this.streams = streams;
        this.game = game;
    }

    @Override
    protected Void doInBackground() throws Exception {
        for(String msg = streams.getIn().readLine(); msg != null; msg = streams.getIn().readLine()){
            System.out.println("bp "  + msg + " " + Thread.currentThread().getId());//TODO remove
            publish(msg);
            System.out.println("ap "  + msg + " " + Thread.currentThread().getId());//TODO remove
        }
        return null;
    }

    @Override
    protected void process(List<String> list) {

        for(String msg = list.remove(0); list.size() != 0; msg = list.remove(0)) {
            System.out.println("dp "  + msg + " " + Thread.currentThread().getId());//TODO remove
            String[] cmds = msg.split(":");
            switch (cmds[0]) {
                case "ADD":
                    game.add(cmds[1], cmds[2], cmds[3]);
                    break;
                case "MOVE":
                    game.remove(cmds[1]);
                    game.add(cmds[1], cmds[2], cmds[3]);
                    break;
                case "REMOVE":
                    game.remove(cmds[1]);
                    break;
                case "BULLETS":
                    //game.addBullets(cmds[1]);
            }
        }
        list.clear();
    }
}

According to the three debug println() when a player moves and the server broadcast it to all the clients the message is read and published but never processed. How could it be?

Answer 1

You are removing messages from the list twice in for loop - list.remove(0):

for(String msg = list.remove(0); list.size() != 0; msg = list.remove(0))

Here is a simple way to iterate a list:

for(String msg : list){
    System.out.println(msg);
}