Scope of thread?

Can anyone tell me what is the scope of a thread and socket...  I am encountering a problem where data returned from my server application is being dropped midway through it. I think maybe the problem is related to garbage collection and object scope.

The following code will listen for a message from a client, then in the ReadWriteSocketThread, it reads the given socket(within run()) and responds with lots of data (3000+ bytes) using the socket.getOutputStream()...  It flushes the stream at every 180 bytes or so. The problem is that the client only receives events for 1 to n of these "flushes"... and sometimes it receives the entire stream.

public class MyServerApplication
{
  public MyServerApplication()
  {
    try
    {
        int listenPort = 800;
        ServerSocket serverSocket = new ServerSocket(listenPort);
        // For each new connection start a thread to handle it
        while (true)
        {
            Socket s = serverSocket.accept();
            System.out.println("Creating a local thread");
            ReadWriteSocketThread thread = new ReadWriteSocketThread (s);
            thread.start();
        }
    }
    catch (Exception e)
    {
        System.out.println("Exception");
        e.printStackTrace();
    }
  }

  public static void main (String args[])
  {
    MyServerApplication server = new MyServerApplication();
  }
}


public class ReadWriteSocketThread extends Thread
{
 public void run()
 {
  try
  {
    int b;
    int len;
    byte[] bt = new byte[4];
    String startMessage = new String ("*START*");

    BufferedInputStream in = new BufferedInputStream(mySocket.getInputStream());
    StringBuffer sb = new StringBuffer();

    boolean isValid = false;
    if (in.read(bt, 0, 4) == 4)
    {
        len = bt[0] * 256 + bt[1];
        System.out.println("Length of string: " + len);
        for (int i = 0; i < len; i ++)
        {
            b = in.read();
            if (b == -1)
                break;
            sb.append((char)b);
        }
        System.out.println("String: " + sb.toString());
        if (sb.toString().equals(startMessage))
        {
            isValid = true;
        }
    }
    if (isValid && in.read(bt, 0, 4) == 4)
    {
        sb.setLength(0);
        len = bt[0] * 256 + bt[1];
        System.out.println("Length of string: " + len);
        for (int i = 0; i < len; i ++)
        {
            b = in.read();
            if (b == -1)
                break;
            sb.append((char)b);
        }
        System.out.println("String: " + sb.toString());
    }
    if (isValid)
    {
        if (in.read(bt, 0, 4) == 4)
        {
            len = bt[0] * 256 + bt[1];
            if (len != 4)
            {
                ErrorLog eLog = new ErrorLog(m_Config);
                eLog.log("Error reading from socket: Message end tag was not found.");
            }
        }
    }

    System.out.println("Received: " + sb.toString());

    // SEND BACK A RESPONSE IN PIECES:
    Responder makeAnswer = new Responder(sb.toString());
    BufferedOutputStream out = new BufferedOutputStream(mySocket.getOutputStream());

    int numResponses = makeAnswer.getNumResponses();
    System.out.println("NumResponses: " + numResponses);

    // numResponses is typically between 15 and 18:
    for (int i = 0; i < numResponses; i ++)
    {
        // response is typically 180 bytes on a good day:
        String response = makeAnswer.getResponse(i);
        //System.out.println ("response: "+ response);
        //System.out.println ("length: "+ response.length());

        int lenOut = response.length()+2;
        out.write(lenOut / 256);
        out.write(lenOut);  
        for (int j=0;j<response.length();j++)
            out.write((byte)(response.charAt(j)));
        out.write(0);
        out.flush();
    }
                        
    out.close();
                  
    in.close();
    m_oSocket.close();  
  } catch (IOException e) {
    //System.out.println ("IOException in Thread");
    ErrorLog eLog = new ErrorLog(m_Config);
    eLog.log("Error reading from socket: "+e.getMessage());
  }
 }
}