How to get status of server side

Question

Dear All,
I have developed the client program for communicating with server (Which can be developed again java or any language and on running on any platform ). So now I can connect with server and continue the communication but suppose if server down or unplugging the network wire, then how I know of that in client side programming. I try to some way but it does not work correctly.
private void  monitor() throws Exception{
              isConnected = s.isConnected() &&
                           !s.isClosed() &&
                            InetAddress.getByName("192.168.1.115").isReachable(1000);
     public void run() {
          while (true){
               try {
                    Thread.sleep(2000);
                    monitor();
                    if(s !=null)
                         System.out.println(isConnected);
               } catch (Exception e) {
                    e.printStackTrace();
     } "s" is the created socket which bound at a one time to continue communication
InetAddress addr = InetAddress.getByName("192.168.1.115");
          SocketAddress sockaddr = new InetSocketAddress(addr,
                    8670);
          Socket s = new Socket();
          s.connect(sockaddr, 5000); Thing is it always print "true " even if the server is down
Can you tell me what is the way to check this ?
Regards
-Kapila

Answer 1

     isConnected = s.isConnected() &&Tells you whether you have called connect(), implicitly or explicitly, or got the socket from an accept().
     !s.isClosed() && Tells you whether you have closed the socket.
Neither of these tells you anything about the state of the connection.
     InetAddress.getByName("192.168.1.115").isReachable(1000);Meaningless.
The only way to tell whether a server can be connected to is to try to connect to it.
The only way to tell whether a server can be written to is to try to write to it, taking network buffering into account.
The only way to tell whether a server can be read from is to set an appropriate read timeout and try to read from it.
TCP doesn't maintain any other information about the state of a connection.