Best way to write objects in an xml and send the file?

Question

hello all
i am making some objects, which i conver to xml using the XStream and then i am saving them to a file, call a function to send the file to a servant (basically i do this by sending bytes and this may be the problem). In the servant i take the data i write them to a file and then i read them again to make them objects...
i have the following code in the client
        XStream xstream = new XStream(new DomDriver());     
        xstream.alias("Jobb", WorkflowFramework.Jobb.class);
     String xml = xstream.toXML(translation);
           FileWriter fw = new FileWriter("translation.xml");
           ObjectOutputStream out = xstream.createObjectOutputStream(fw);
           out.writeObject(new Jobb("ougk2", "Walnes",null));
           out.close();
           File file=new File("translation.xml");
           byte buffer[]=new byte[(int)file.length()];
           try {
                BufferedInputStream input=new BufferedInputStream(new FileInputStream("translation.xml"));
                input.read(buffer,0,buffer.length);
                input.close();
           } catch(Exception e) {
                  System.out.println("Error: "+e.getMessage());
                   e.printStackTrace();
           theRemoteObjRef.translationService(theCallbackObjectRef, buffer);i write the file and then i read it so as to have a buffer of bytes (there should be a better ways..)
the last line sends an objectRef (we dont care about that) and the file in bytes to a server (to be specific to a servant of a server)..
in the servant i do the following
public void translationService(TheCallbackInterface objRef, byte data[]){
          try{
                    File file = new File("translation2.xml");
                BufferedOutputStream output = new BufferedOutputStream(new FileOutputStream("translation2.xml"));
              output.write(data, 0, data.length);
              output.flush();
              output.close();
          } catch(Exception e) {
                    System.out.println("Error: " + e.getMessage());
                    e.printStackTrace();
           XStream xstream = new XStream(new DomDriver());
           try { // If an error occurs, go to the "catch" block
                FileReader fr2 = new FileReader("translation2.xml");
                ObjectInputStream in = xstream.createObjectInputStream(fr2);
                Jobb newJob = (Jobb)in.readObject();
               System.out.println(newJob.getObjServerRef());
               System.out.println(newJob.getForTranslation());
               System.out.println(newJob.getTranslated());
                }catch (Exception e) {  
                     System.err.println("File input error"+e);
                Jobb testJob=new Jobb("ougka","mpougka","falalala");
                System.out.println(testJob.getObjServerRef());
                   System.out.println(testJob.getForTranslation());
                System.out.println(testJob.getTranslated());
the problem is that in the first group of System.out.println i get the error File input errorcom.thoughtworks.xstream.mapper.CannotResolveClassException: Jobb : Jobb
but the second group of printlns, prints the correct results...
do you know what is the problem? Why can i read the content of the file and get the objects from there?
do you have any suggestions of writing and reading the file in an another way or to send it by NOT using a bytes array?
do you have an alternative way of making the xml file?
many thanks!

Answer 1

Hi,
I would suggest to reconsider building of your document so that it doesn't contain duplicates if you don't need them. And it doesn't have much to do with DB XML then.
Also you could insert your document with duplicates and use XQuery Update facilities to delete undesirable nodes.
Vyacheslav