Ping Pong Server/Client problem

So basically I have to make the server and client "Ping" and "Pong" back and forth to each other 10 times, using a command line argument. They compile, but I keep getting an ArrayIndexOutOfBoundsException, which I know means my numbers are wrong somewhere... I think. I've tried testing different numbers, but I can't get it to stop throwing the exception. Suggestions?

Code:

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import java.io.*;
import java.net.*;
import java.lang.*;

public class Ponger // SERVER
{
        public void go()
        {
        try
                {
            ServerSocket serverSocket = new ServerSocket(24047);

            while(true)
            {
                Socket sock = serverSocket.accept();
                PrintWriter writer = new PrintWriter(sock.getOutputStream());

                for (int i = 0; i < 11; i++)
                {
                    System.out.println("Pong");
                    writer.flush();
                    writer.close();
                        }
            }
        }
            catch (IOException ex)
                  {
                    ex.printStackTrace();
            }
    }

                public static void main(String[] args)
                {
            int numPlays = Integer.parseInt(args[0]); // Tried 10 and 0, no luck
                        Ponger ponger = new Ponger();
                        ponger.go();
                }
}

---

Code:

---

import java.io.*;
import java.net.*;
import java.lang.*;
public class Pinger // CLIENT
{
    public void go()
    {
        try
        {
            Socket s = new Socket("127.0.0.1", 24047);                                 
            InputStreamReader streamReader = new InputStreamReader(s.getInputStream());   
            BufferedReader reader  = new BufferedReader(streamReader);                               
            PrintWriter writer = new PrintWriter(s.getOutputStream());
           
            for (int i = 0; i < 11; i++)
            {
                System.out.println("Ping");
               
                writer.flush();
                writer.close();
            }
        }
        catch (IOException ex)
        {
            ex.printStackTrace();
        }
    }

    public static void main(String[] args)
    {
        int numPlays = Integer.parseInt(args[0]); // I tried 10 and 0, no luck
        Pinger pinger = new Pinger();
        pinger.go();
    }
}

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