Weird server program behaviour...

[doy2001]

Hi! I have a question regarding a simple server program included as a sample on my Core Java book. Here´s the code:

/**
 * @version 1.10 1997-06-27
 * @author Cay Horstmann
 */

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

/**
   This program implements a simple server that listens to
   port 8189 and echoes back all client input.
*/
public class EchoServer
{  
   public static void main(String[] args )
   {  
      try
      {  
         // establish server socket
         ServerSocket s = new ServerSocket(8189);

         // wait for client connection
         Socket incoming = s.accept( ); 
         BufferedReader in = new BufferedReader
            (new InputStreamReader(incoming.getInputStream()));
         PrintWriter out = new PrintWriter
            (incoming.getOutputStream(), true /* autoFlush */);

         out.println( "Hello! Enter BYE to exit.");

         // echo client input
         boolean done = false;
         while (!done)
         {  
            String line = in.readLine();
            if (line == null) done = true;
            else
            {  
               out.println("Echo: " + line);
               if (line.trim().equals("BYE"))
                  done = true;
            }
         }
         
         incoming.close();
         
      }
      catch (Exception e)
      {  
         e.printStackTrace();
      }
   }
}

Ok, try running the program yourselves and then open a local connection on port 8189. My question is: it seems the "while" is not running while done == false... it seems to run only when the server gets input. Why is this? it should run always, and read a line from the BufferedReader always. If the buffer has nothing, then there is no line, and done = true. So practically the program should end up a second after starting.
Thanks for your help... this is driving me nuts!