请教一个java socket的问题

public class EchoServer

{

    public static void main(String[] args)

    {

        try

        {

            ServerSocket s = new ServerSocket(8189);

            Socket incoming = s.accept();

            try

            {

                InputStream inStream = incoming.getInputStream();

                OutputStream outStream = incoming.getOutputStream();

      

                Scanner in = new Scanner(inStream);

                PrintWriter out = new PrintWriter(outStream, true);

   

                out.println("hello! enter BYE to exit.");



                boolean done = false;



                while(!done && in.hasNextLine())

                {

                   String line = in.nextLine();

                   out.println("Echo:" + line);

                   if(line.trim().equals("BYE"))

                          done = true;

                }

           }

           finally

           { incoming.close();}

      }

      catch(IOException e)

      {

       }



 }

}