Socket Threading Example

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.Socket;
import java.net.ServerSocket;
import java.util.ArrayList;

public class Main {

    private ArrayList<SocketManager> managers = new ArrayList<SocketManager>();

    public void startReceivingConnections() {
        final ServerSocket server;
        try {
            server = new ServerSocket(1234);

            /* create a thread that will constantly wait for new connections
             * then add them to the list, alerting all other connected hosts
             */
            new Thread(new Runnable() {
                public void run() {
                    while (true) {
                        Socket s;
                        try {
                            s = server.accept();
                            writeToAll("New connection!");
                            managers.add(new SocketManager(s));
                        } catch (IOException e) {
                            //handle
                        }
                    }
                }
            }).start();
        } catch (IOException e) {
            //handle
        }
    }

    public void writeToAll(String message) throws IOException {
        for (SocketManager m : managers) {
            m.write(message);
        }
    }

    public static void main(String[] args) {
        Main m = new Main();
        m.startReceivingConnections();
    }
}

class SocketManager {
    private Socket socket;
    private DataInputStream inputStream;
    private DataOutputStream outputStream;
    private Thread readThread;
    private boolean shouldCancel = false;

    public SocketManager(Socket s) throws IOException {
        socket = s;
        inputStream = new DataInputStream(s.getInputStream());
        outputStream = new DataOutputStream(s.getOutputStream());

        //putting the read on a separate thread allows us to write at any time
        readThread = new Thread(new Runnable() {
            public void run() {
                while (!shouldCancel) {
                    try {
                        String line = inputStream.readUTF();
                        System.out.println(line);
                    } catch (IOException e) {
                        //handle exception
                    }
                }
            }
        });
        readThread.start();
    }

    public void write(String s) {
        try {
            outputStream.writeUTF(s);
        } catch (IOException e) {
            //handle
        }
    }

    public void cancel() {
        try {
            shouldCancel = true; //do this instead of calling the deprecated readThread.stop()
            socket.close();
        } catch (IOException e) {
            //handle
        }
    }
}