Problem with Socket Programming

Question

Hi
I have used java sockets in my program for installing a tool on different boxes.On running this server program on a linux box my client program is unable to listen to the socket on the linux box.It give a
ConnectionRefused exception in the client program which is running on the windows box.This behaviour is pretty inconsistent though.The version of linux is redhat 7.3 and the kernel is 2.4.18-3 on au i686 (valhalla) and the java version on the
linux ->1.4.0_01-b03,mixed mode.
The windows box also has j2sdk1.4.0.
Please reply urgently.

Answer 1

I have used the same source to open sockets on windows and on solaris and it has worked consistenly.It is only the linux box that is inconsistent in listening to the sockets.
On the server i have used this part to open the socket:
public void process() throws Exception {
          SocketChannel sc = null;
          ServerSocketChannel ssc = null;
          Selector acceptSelector = null;
          try {
               int port = Integer.parseInt(resourceBundle.getString("AUTH_PORT"));
               System.out.println("Listening on Port:: "+port);
               int socketTimeOut = Integer.parseInt(resourceBundle.getString("SOCKET_TIMEOUT"));
               acceptSelector = SelectorProvider.provider().openSelector();
               ssc = ServerSocketChannel.open();
               ssc.configureBlocking(false);
               InetAddress lh = InetAddress.getLocalHost();
               InetSocketAddress isa = new InetSocketAddress(lh, port);
               ssc.socket().bind(isa);
               SelectionKey acceptKey = ssc.register(acceptSelector,SelectionKey.OP_ACCEPT);
               int keysAdded = 0;
               while ((keysAdded = acceptSelector.select()) > 0) {
                    // Someone is ready for I/O, get the ready keys
                    Set readyKeys = acceptSelector.selectedKeys();
                    Iterator i = readyKeys.iterator();
                    // Walk through the ready keys collection and process date requests.
                    while (i.hasNext()) {
                         boolean processFlag = true;
                         SelectionKey sk = (SelectionKey)i.next();
                         i.remove();
                         // The key indexes into the selector so you
                         // can retrieve the socket that's ready for I/O
                         ServerSocketChannel nextReady = (ServerSocketChannel)sk.channel();
                         // Accept the date request and send back the date string
                         sc = nextReady.accept();
                         so = sc.socket();
                         writeToLogFile ("Socket is ::"+so+"::",4);
//                         so.setSoTimeout(socketTimeOut);
                         writeToLogFile ("Before receiveAuthReqMessage",4);
                         ois = new ObjectInputStream(so.getInputStream());
                         receiveAuthReqMessage();     // receive AuthReqMessage.xml
                         writeToLogFile ("After receiveAuthReqMessage::"+processFlag,4);
//                         readAuthReqMessageData();     // reads the userName, password for validation
                         authenticate();                    // validates username & password of client
                         sendAuthResMessage();          // feedback to client AuthResMessage.xml
                         if(validbool)
                              while (processFlag) {
                                   processFlag = receiveRegReqMessage();
                         else
                              writeToLogFile ("INVALID : You are NOT a VALID user .......",0);
                         writeToLogFile ("Just before closing",4);
                         ois.close();
//                         sc.close();
//                         so.close();
          } catch (Exception e) {
          e.printStackTrace();
          finally {
               os.close();
               sc.close();
               ssc.close();
               acceptSelector.close();
               so.close();
and on the client part of the program i use this code to make the client listen to the server program:
     public boolean openAuthSocket(String machineName) {
          try{
               int portNo = 0;
               ResourceBundle resourceBundle = ResourceBundle.getBundle("GPSClientProperties", locale);
                    portNo = Integer.parseInt(resourceBundle.getString("AUTH_PORT"));
               if (machineName == null) {
                    machineName = resourceBundle.getString("AUTH_MACHNAME");
               authsocket =new Socket(machineName,portNo);
               writeToLogFile("Authentication socket OPENED on authsocket: " +authsocket,4);
               int socketTimeOut = Integer.parseInt(resourceBundle.getString("SOCKET_TIMEOUT"));
               authsocket.setSoTimeout(socketTimeOut);
          }catch (Exception e){
               writeToLogFile("The exception in open socket is "+e,0);
e.printStackTrace();
               return false;
          return true;