public String echo(String input)throws java.rmi.RemoteException {
	connect();
    if (echoSocket != null && os != null && is != null) {
  	try {
             os.println(input);
             os.flush();
             output= is.readLine();
      } catch (IOException e) {
        System.err.println("I/O failed in reading/writing socket");
      }
    }
    disconnect();
    return output;
  }