Saving java objects without serialization

Hi!
I want to save a lot of java objects to file, and be able to restore the data structure that these java objects compose.
The obvious way to do that, is to use some kind of serialization I guess. But, as I see it, the problem with this approach is that as the data structure expands and new classes are added and present classes are changed (even the name of the classes) this approach fails. If the user has an old data structure that he/she wants to restore there will be a problem with e.g. ClassCastException and the like.
Now I am wondering if someone could give me some hints of how to solve this problem. What approach should I use instead. Is XML the right way to do it? Someone who has any experience with these problems?
I would really appreciate some help!
Best regards
Lars

Hi, Lars, funny you should mention this issue. I am
dealing with the exact same problem at work. Every
time I release a new version of my software, users
cannot load files they saved with the previous
version. This is a big problem !
And, like you, I am toying with the XML solution.
On the downside, saving these objects in an XML format
will take more memory, as XML can be (and should be?)
textually descriptive. Those ASCII tags and such will
probably treble the file size of their streamlined
"serialized" predecessors.
But memory is cheap, eh ?
On the plus side, your XML parser can be (by it's nature)
forgiving if new fields have been added or old ones taken
away. And that is why Serializable is giving be a headache
to begin with !
Two other thoughts cross my mind ...
For exceedingly large files, a SAX parser (vice DOM) will
only have a bit 'o the structure in memory at a time, instead
of having the whole kit and kaboodle in memory (my understanding
of DOM).
Also, nothing is stopping me from taking a gander at some of
the Zip packages ... now where did I run across them ? java.io ? ...
where once I write out the XML file (saving my objects), I could
compress 'em for the user, too :-) I seem to recall a ZipStream or
something while scanning some of the (JDK 1.4?) packages.
I am looking forward to your response, and those of other interested
readers sharing their thoughts on this topic, too !
Eric

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Dear Sir:
I met a problem as demo in my code below when i use XTream to persist my Java Object;
How can I use XStream to persist complicated Java Object to XML & backward??
See
[1] main code
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.ArrayList;
import com.thoughtworks.xstream.XStream;
import com.thoughtworks.xstream.io.xml.DomDriver;
public class PhoneList {
     ArrayList<PhoneNumber> phones;
     ArrayList<Person> person;
     private PhoneList myphonelist ;
     private LocationTest location;
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     person = new ArrayList<Person>();
     public ArrayList<PhoneNumber> getphones() {
          return phones;
     public ArrayList<Person> getperson() {
          return person;
     public void addPhoneNumber(PhoneNumber b1) {
          this.phones.add(b1);
     public void removePhoneNumber(PhoneNumber b1) {
          this.phones.remove(b1);
     public void addPerson(Person p1) {
          this.person.add(p1);
     public void removePerson(Person p1) {
          this.person.remove(p1);
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          joe.setPhone(new PhoneNumber(123, "1234-456"));
          joe.setFax(new PhoneNumber(123, "9999-999"));
          Person geo= new Person("George Nixson");
          geo.setPhone(new PhoneNumber(925, "228-9999"));
          geo.getPhone().setLocationTest(location);
          myphonelist.addPerson(joe);
          myphonelist.addPerson(geo);
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          BuildList();
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          BufferedWriter bw = null;
          try {
               bw = new BufferedWriter(
                         new FileWriter(fileName));
               try {
                    bw.write(saveString);
               finally {
                    bw.close();
          catch (IOException ex) {
               ex.printStackTrace();
          //return saved;
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          BufferedReader br = null;
          StringBuilder sb = new StringBuilder();
          try {
               br = new BufferedReader(
                         new FileReader(fileName));
               try {
                    String s;
                    while ((s = br.readLine()) != null) {
                         // add linefeed (\n) back since stripped by readline()
                         sb.append(s + "\n");
               finally {
                    br.close();
          catch (Exception ex) {
               ex.printStackTrace();
          return sb.toString();
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          XStream xstream = new XStream(new DomDriver());
          xstream.setMode(xstream.ID_REFERENCES) ;
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          new PhoneList();
}[2].
import java.io.Serializable;
import javax.swing.JFrame;
public class PhoneNumber implements Serializable{
       private      String      phone;
       private      String      fax;
       private      int      code;
       private      String      number;
       private      String      address;
       private      String      school;
       private      LocationTest      location;
       public PhoneNumber(int i, String str) {
            setCode(i);
            setNumber(str);
            address = "4256, Washington DC, USA";
            school = "Washington State University";
     public Object getPerson() {
          return null;
     public void setPhone(String phone) {
          this.phone = phone;
     public String getPhone() {
          return phone;
     public void setFax(String fax) {
          this.fax = fax;
     public String getFax() {
          return fax;
     public void setCode(int code) {
          this.code = code;
     public int getCode() {
          return code;
     public void setNumber(String number) {
          this.number = number;
     public String getNumber() {
          return number;
     public void setLocationTest(LocationTest bd) {
          this.location = bd;
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.getContentPane().add(location);
        f.getContentPane().add(location.getControls(), "Last");
        f.setSize(400,400);
        f.setLocation(200,200);
        f.setVisible(true);
     public LocationTest getLocationTest() {
          return location;
     }[3].
package test.temp;
import java.io.Serializable;
public class Person implements Serializable{
     private String           fullname;
       @SuppressWarnings("unused")
     private PhoneNumber      phone;
       @SuppressWarnings("unused")
     private PhoneNumber      fax;
     public Person(){
     public Person(String fname){
            fullname=fname;
     public void setPhone(PhoneNumber phoneNumber) {
          phone = phoneNumber;
     public void setFax(PhoneNumber phoneNumber) {
          fax = phoneNumber;
     public PhoneNumber getPhone() {
          return phone ;
     public PhoneNumber getFax() {
          return fax;
    public String getName() {
        return fullname ;
    public void setName(String name) {
        this.fullname      = name;
    public String toString() {
        return getName();
}[4]. LocationTest.java
package test.temp;
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import javax.swing.*;
import javax.swing.event.*;
public class LocationTest extends JPanel implements ChangeListener
    Ellipse2D.Double ball;
    Line2D.Double    line;
    JSlider          translate;
    double           lastTheta = 0;
    public void stateChanged(ChangeEvent e)
        JSlider slider = (JSlider)e.getSource();
        String name = slider.getName();
        int value = slider.getValue();
        if(name.equals("rotation"))
            tilt(Math.toRadians(value));
        else if(name.equals("translate"))
            moveBall(value);
        repaint();
    protected void paintComponent(Graphics g)
        super.paintComponent(g);
        Graphics2D g2 = (Graphics2D)g;
        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                            RenderingHints.VALUE_ANTIALIAS_ON);
        if(ball == null)
            initGeom();
        g2.setPaint(Color.green.darker());
        g2.draw(line);
        g2.setPaint(Color.red);
        g2.fill(ball);
    private void initGeom()
        int w = getWidth();
        int h = getHeight();
        int DIA = 30;
        int padFromEnd = 5;
        line = new Line2D.Double(w/4, h*15/16, w*3/4, h*15/16);
        double x = line.x2 - padFromEnd - DIA;
        double y = line.y2 - DIA;
        ball = new Ellipse2D.Double(x, y, DIA, DIA);
        // update translate slider values
        int max = (int)line.getP1().distance(line.getP2());
        translate.setMaximum(max);
        translate.setValue(max-padFromEnd);
    private void tilt(double theta)
        // rotate line from left end
        Point2D pivot = line.getP1();
        double lineLength = pivot.distance(line.getP2());
        Point2D.Double p2 = new Point2D.Double();
        p2.x = pivot.getX() + lineLength*Math.cos(theta);
        p2.y = pivot.getY() + lineLength*Math.sin(theta);
        line.setLine(pivot, p2);
        // find angle from pivot to ball center relative to line
        // ie, ball center -> pivot -> line end
        double cx = ball.getCenterX();
        double cy = ball.getCenterY();
        double pivotToCenter = pivot.distance(cx, cy);
        // angle of ball to horizon
        double dy = cy - pivot.getY();
        double dx = cx - pivot.getX();
        // relative angle phi = ball_to_horizon - last line_to_horizon
        double phi = Math.atan2(dy, dx) - lastTheta;
        // rotate ball from pivot
        double x = pivot.getX() + pivotToCenter*Math.cos(theta+phi);
        double y = pivot.getY() + pivotToCenter*Math.sin(theta+phi);
        ball.setFrameFromCenter(x, y, x+ball.width/2, y+ball.height/2);
        lastTheta = theta; // save theta for next time
    private void moveBall(int distance)
        Point2D pivot = line.getP1();
        // ball touches line at distance from pivot
        double contactX = pivot.getX() + distance*Math.cos(lastTheta);
        double contactY = pivot.getY() + distance*Math.sin(lastTheta);
        // find new center location of ball
        // angle lambda = lastTheta - 90 degrees (anti-clockwise)
        double lambda = lastTheta - Math.PI/2;
        double x = contactX + (ball.width/2)*Math.cos(lambda);
        double y = contactY + (ball.height/2)*Math.sin(lambda);
        ball.setFrameFromCenter(x, y, x+ball.width/2, y+ball.height/2);
    JPanel getControls()
        JSlider rotate = getSlider("rotation angle", "rotation", -90, 0, 0, 5, 15);
        translate = getSlider("distance from end", "translate", 0, 100, 100,25, 50);
        JPanel panel = new JPanel(new GridLayout(0,1));
        panel.add(rotate);
        panel.add(translate);
        return panel;
    private JSlider getSlider(String title, String name, int min, int max,
                              int value, int minorSpace, int majorSpace)
        JSlider slider = new JSlider(JSlider.HORIZONTAL, min, max, value);
        slider.setBorder(BorderFactory.createTitledBorder(title));
        slider.setName(name);
        slider.setPaintTicks(true);
        slider.setMinorTickSpacing(minorSpace);
        slider.setMajorTickSpacing(majorSpace);
        slider.setPaintLabels(true);
        slider.addChangeListener(this);
        return slider;
}OK, My questions are:
[1]. what I generated XML by XSTream is very complicated, especially for object LocationTest, Can we make it as simple as others such as Person object??
[2]. after I run it, LocationTest will popup and a red ball in a panel will dsiplay, after I change red ball's position, I hope to persist it to xml, then when I read it back, I hope to get same picture, ie, red ball stiil in old position, How to do that??
Thanks a lot!!

Positive feedback? Then please take this in a positive way: if you want to work on persisting Java objects into XML, then GUI programming is irrelevant to that goal. The 1,000 lines of code you posted there appeared to me to have a whole lot of GUI code in it. You should produce a smaller (much smaller) example of what you want to do. Calling the working code from your GUI program should come later.

Domain design causing full object graph serialization

Hello,
I work on a project, based on 3-layer-architecture. We have rich client developed on swing, application server and we persist our domain objects in the database.
We map the domain objects using hibernate, send the same objects (means, we use POJOs and don't use DTO) via spring from application server to the server and visa versa in case the objects are to be saved, deleted etc.
We use an object identity store on the client side, in which all already loaded objects are stored.
My challenge is as follows:
- Since an object is stored in the object store, the same certain object is used in every GUI module. Imagine, we have customer, account and a list of transactions per account. In practice, let's say:
1 customer
2 accounts
1000 transactions per account which ever exist
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- On another module, the user wants to edit a very small attribute of customer object, say he corrects his birthday date and saves it.
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service.save(customer);is called, and this costs extremely much time for our application.
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So the problem for the save-use case was solved. This has a disadventage: the loading time (server-client (de-)serialization) using xml is longer than the java standard, especially remarkable if you load a big number of objects.
I've read many articles about the enterprise architectures which are related to domain objects, dto, serialization. It is not uncommon to avoid DTOs and use POJOs on the server and client as well, if the domain objects don't contain business logic. So, I just wonder, how the problem above should be solved smartly, if the non-DTO, say POJO alternative is chosen.
I appreciate your opinions.
I hope my question is not too long. Thanks in advance,
A sample code:
(The concrete case in our application requires the navigability from customer to account)
public class Customer implements Serializable {
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acelik wrote:
Thanks for the quick answer.
The numbers are just wildly guesses, in order to keep the sample simple.
Actually we develop a system for automobile industry. So, instead of customer, you may think of a company, like Ford. Account would be then Fiesta. Instead of AccTransaction we may think a huge number of car pieces (clima, motor, radio, etc.).
So hierarchically we have
Company (Ford, Opel, etc)
Model (Fiesta, Astra, etc.)
Piece (1000 pieces per model, so Fiesta, Opel have 1000 different pieces each)
The problem is, if I loaded the Ford->Fiesta->1000x pieces for one view and then switch to another view. In the second view, I rename Fiesta to Fiesta II, and want to save this renaming operation using:
What exactly does that represent?
If you want to rename an existing car then you need logic to do exactly that. You do not copy the entire tree.
If however you do want to copy the entire tree then that is in fact what you must do. Although I seriously doubt that there is a valid business requirement for that. In terms of efficiency though you could write a proc that did that rather than propogating the tree.
Although further if you do in fact have two cars which use the same inventory item(s) then, again, you do not copy the entire tree because you are not creating a brand new inventory item. Instead you should only be pointing to an existing item.
I wonder how this problem is solved smartly, if you guys share domain objects between the client and server, and avoid DTO.The first step is to start with actual business requirements.

Generation of XML file from Java objects using castor

I have the following java file(Customer.java).
public class Customer
     private String ID;
     private FirstName firstName;
     private MiddleName middleName;
     private LastName lastName;
     private ArrayList address;
     public ArrayList getAddress() {
          return address;
     public void setAddress(ArrayList address) {
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          this.firstName = firstName;
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          return lastName;
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          this.lastName = lastName;
     public MiddleName getMiddleName() {
          return middleName;
     public void setMiddleName(MiddleName middleName) {
          this.middleName = middleName;
Using castor i have created an xml file(customer.xml) which has the following format.
<?xml version="1.0" encoding="UTF-8" ?>
- <customer ID="fbs0001">
<FIRSTNAME>Fred</FIRSTNAME>
<MIDDLENAME>B</MIDDLENAME>
<LASTNAME>Scerbo</LASTNAME>
- <ADDRESS>
<FIRSTLINE>No 18, Sheshadri road</FIRSTLINE>
<SECONDLINE>Gandhinagar Bangalore</SECONDLINE>
</ADDRESS>
- <ADDRESS>
<FIRSTLINE>ITPL</FIRSTLINE>
<SECONDLINE>Whitefield Bangalore</SECONDLINE>
</ADDRESS>
</customer>
I have used a mapping file to get this output.Is there a way where i can get the output xml in the following format without changing the Java object structure.If yes then please suggest how this can be done.
<?xml version="1.0" encoding="UTF-8" ?>
- <customer ID="fbs0001">
<FIRSTNAME>Fred</FIRSTNAME>
<MIDDLENAME>B</MIDDLENAME>
<LASTNAME>Scerbo</LASTNAME>
</customer>
<ADDRESS>
<FIRSTLINE>No 18, Sheshadri road</FIRSTLINE>
<SECONDLINE>Gandhinagar Bangalore</SECONDLINE>
</ADDRESS>
- <ADDRESS>
<FIRSTLINE>ITPL</FIRSTLINE>
<SECONDLINE>Whitefield Bangalore</SECONDLINE>
</ADDRESS>
I mean the output xml file should have the address as a separate tag not withing the root tag customer.

Hello,
Castor's own discussion groups might be able to point you to the solution you're looking for (if this use case is possible using Castor).
Oracle has its own object-to-XML mapping tool that is part of the TopLink product. It allows you to map existing objects to an existing XML Schema. This can be done visually using the TopLink Workbench, or programmatically using the TopLink APIs. TopLink OXM also supports the JAXB specification.
Using TopLink OXM to get the desired XML result I would recommend the following. Map the Customer and Address classes to XML, but don't map the relationship between Customer and Address. Then make the calls to the marshaller something like the following:
marshaller.marshal(aCustomer, System.out);
for(int x=0; x<aCustomer.getAddress().size(); x++) {
     marshal(aCustomer.getAddress().get(x), System.out);
Example - Using TopLink OXM to map an existing object model to an existing XML Schema:
http://www.oracle.com/technology/products/ias/toplink/preview/10.1.3dp4/howto/ox/index.htm
For more information on TopLink object-to-XML mapping:
http://www.oracle.com/technology/products/ias/toplink/preview/10.1.3dp4/objectxml/index.html
-Blaise

Reg XML generation from java objects using SAX 2.0

i'm using java 1.6 and i've imported following class to generate XML from java objects
import com.sun.org.apache.xml.internal.serialize.OutputFormat;
import com.sun.org.apache.xml.internal.serialize.XMLSerializer;
the following class has been imple her to create a Xml file and tag elements ,
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hd.startDocument();
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warring is:
com.sun.org.apache.xml.internal.serialize.OutputFormat is Sun proprietary API and may be removed in a future release
com.sun.org.apache.xml.internal.serialize.OutputFormat is Sun proprietary API and may be removed in a future release
HOW CAN I AVOID DS WARRING PLZ HELP REG DS
thanks ,
with regards,
Rajesh.S

I've been having the same problem. Here is what i found:
[http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6476630]
Hope that helps (or at least helps you feel better).

How to get an XML string from a Java Bean without wrting to a file first ?

I know we can save a Java Bean to an XML file with XMLEncoder and then read it back with XMLDecoder.
But how can I get an XML string of a Java Bean without writing to a file first ?
For instance :
My_Class A_Class = new My_Class("a",1,2,"Z", ...);
String XML_String_Of_The_Class = an XML representation of A_Class ?
Of course I can save it to a file with XMLEncoder, and read it in using XMLDecoder, then delete the file, I wonder if it is possible to skip all that and get the XML string directly ?
Frank

I think so too, but I am trying to send the object to a servlet as shown below, since I don't know how to send an object to a servlet, I can only turn it into a string and reconstruct it back to an object on the server side after receiving it :
import java.io.*;
import java.net.*;
import java.util.*;
class Servlet_Message        // Send a message to an HTTP servlet. The protocol is a GET or POST request with a URLEncoded string holding the arguments sent as name=value pairs.
public static int GET=0;
public static int POST=1;
private URL servlet;
// the URL of the servlet to send messages to
public Servlet_Message(URL servlet) { this.servlet=servlet; }
public String sendMessage(Properties args) throws IOException { return sendMessage(args,POST); }
// Send the request. Return the input stream with the response if the request succeeds.
// @param args the arguments to send to the servlet
// @param method GET or POST
// @exception IOException if error sending request
// @return the response from the servlet to this message
public String sendMessage(Properties args,int method) throws IOException
    String Input_Line;
    StringBuffer Result_Buf=new StringBuffer();
    // Set this up any way you want -- POST can be used for all calls, but request headers
    // cannot be set in JDK 1.0.2 so the query string still must be used to pass arguments.
    if (method==GET)
      URL url=new URL(servlet.toExternalForm()+"?"+toEncodedString(args));
      BufferedReader in=new BufferedReader(new InputStreamReader(url.openStream()));
      while ((Input_Line=in.readLine()) != null) Result_Buf.append(Input_Line+"\n");
    else
      URLConnection conn=servlet.openConnection();
      conn.setDoInput(true);
      conn.setDoOutput(true);
      conn.setUseCaches(false);
      // Work around a Netscape bug
      conn.setRequestProperty("Content-Type","application/x-www-form-urlencoded");
      // POST the request data (html form encoded)
      DataOutputStream out=new DataOutputStream(conn.getOutputStream());
      if (args!=null && args.size()>0)
        out.writeBytes(toEncodedString(args));
//        System.out.println("ServletMessage args: "+args);
//        System.out.println("ServletMessage toEncString args: "+toEncodedString(args));
      BufferedReader in=new BufferedReader(new InputStreamReader(conn.getInputStream()));
      while ((Input_Line=in.readLine()) != null) Result_Buf.append(Input_Line+"\n");
      out.flush();
      out.close(); // ESSENTIAL for this to work!
    return Result_Buf.toString();               // Read the POST response data
// Encode the arguments in the property set as a URL-encoded string. Multiple name=value pairs are separated by ampersands.
// @return the URLEncoded string with name=value pairs
public String toEncodedString(Properties args)
    StringBuffer sb=new StringBuffer();
    if (args!=null)
      String sep="";
      Enumeration names=args.propertyNames();
      while (names.hasMoreElements())
        String name=(String)names.nextElement();
        try { sb.append(sep+URLEncoder.encode(name,"UTF-8")+"="+URLEncoder.encode(args.getProperty(name),"UTF-8")); }
//        try { sb.append(sep+URLEncoder.encode(name,"UTF-16")+"="+URLEncoder.encode(args.getProperty(name),"UTF-16")); }
        catch (UnsupportedEncodingException e) { System.out.println(e); }
        sep="&";
    return sb.toString();
}As shown above the servlet need to encode a string.
Now my question becomes :
<1> Is it possible to send an object to a servlet, if so how ? And at the receiving end how to get it back to an object ?
<2> If it can't be done, how can I be sure to encode the string in the right format to send it over to the servlet ?
Frank

Parse of a xml file to an java object model

Hello,
I'm trying to do a program that receive an xml file and ought to create all the neccesary java objects according to the content of the parsed xml file.
I've all the class created for all the objects that could be present into the xml and the idea is to go down in the tree of nodes recursively until it returns nodes more simple. Then, I create the last object and while I come back of the recursively calls, I create the objects more complex until I reached to the main object.
Until now, I have part of this code, that is the one wich have to parse the parts of the xml.
public static void readFile(String root){
          DocumentBuilderFactory factory = DocumentBuilderFactory
               .newInstance();
          try {
               DocumentBuilder builder = factory.newDocumentBuilder();
               Scanner scanner = new Scanner(new File(root)).useDelimiter("\\Z");
               String contents = scanner.next();
               scanner.close();
               Document document = builder.parse(new ByteArrayInputStream(contents.getBytes()));
               Node node = null;
               NodeList nodes = null;
               Element element = document.getDocumentElement();
               System.out.println(element.getNodeName());
               NodeList subNodes;
               NamedNodeMap attributes;
               //if (element.hasAttributes())
               visitNodes(element);
          } catch (ParserConfigurationException e) {
               e.printStackTrace();
          } catch (SAXException e) {
               e.printStackTrace();
          } catch (IOException e) {
               e.printStackTrace();
     private static void visitNodes (Node node){
          for(Node childNode = node.getFirstChild(); childNode!=null;){
               if (childNode.getNodeType() == childNode.DOCUMENT_NODE){
                    System.out.println("Document node Name " + childNode.getNodeName());
                    visitNodes(childNode);
               }else if (childNode.getNodeType() == childNode.ELEMENT_NODE){
                    System.out.println("Node Name " + childNode.getNodeName());
                    if (childNode.hasAttributes()){
                         visitAttributes(childNode.getAttributes());
                    if (childNode.hasChildNodes()){
                         visitNodes(childNode);
               }else if (childNode.getNodeType() == childNode.TEXT_NODE && !childNode.getNodeValue().contains("\n\t")){
                    System.out.println("Node value " + childNode.getNodeValue());
               Node nextChild = childNode.getNextSibling();
               childNode = nextChild;
     private static void visitAttributes(NamedNodeMap attributes){
          Node node;
          for(int i = 0; i < attributes.getLength(); i++){
               node = attributes.item(i);
               System.out.print(node.getNodeName() + " ");
               System.out.print(node.getNodeValue() + " ");
              }I don't know the use of childNodeType. For example, I expected that the XML tags with childs in his structure, enter by the option NODE_DOCUMENT and the tags without childs by the ELEMENT_NODE.
But the most important problem I've found are the nodes [#text] because after one ELEMENT_NODE I always found this node and when I ask if the node hasChilds, always returns true by this node.
Has any option to obtain this text value, that finally I want to display without doing other recursively call when I enter into the ELEMENT_NODE option?
When one Node is of type DOCUMENT_NODE or DOCUMENT_COMMENT? My program always enter by the ELEMENT_NODE type
Have you any other suggestions? All the help or idea will be well received.
Thanks for all.

Hello again,
My native language is Spanish and sorry by my English I attemp write as better I can, using my own knowledge and the google traductor.
I have solved my initial problem with the xml parser.
Firstly, I read the complete XML file, validated previously.
The code I've used is this:
public static String readCompleteFile (String root){
          String content = "";
          try {
               Scanner scanner = new Scanner(new File(root)).useDelimiter("\\Z");
               content = scanner.next();
               scanner.close();
          } catch (IOException e) {
               e.printStackTrace();
          return content;
     }Now, I've the file in memory and I hope I can explain me better.
I can receive different types of XML that could be or not partly equals.
For this purpose I've created an external jar library with all the possible objects contained in my xml files.
Each one of this objects depend on other, until found leaf nodes.
For example, If I receive one xml with a scheme like the next:
<Person>
    <Name>Juliet</Name>
    <Father Age="30r">Peter</Father>
    <Mother age="29">Theresa</Mother>
    <Brother>
    </Brother>
    <Education>
        <School>
        </school>
    </education>
</person>
<person>
</person>The first class, which initializes the parse, should selecting all the person tags into the file and treat them one by one. This means that for each person tag found, I must to call each subobject wich appears in the tag. using as parameter his own part of the tag and so on until you reach a node that has no more than values and or attributes. When the last node is completed I'm going to go back for completing the parent objects until I return to the original object. Then I'll have all the XML in java objects.
The method that I must implement as constructor in every object is similar to this:
public class Person{
final String[] SUBOBJETOS = {"Father", "Mother", "Brothers", "Education"};
private String name;
     private Father father;
     private Mother mother;
     private ArrayList brothers;
     private Education education;
     public Person(String xml){
       XmlUtil utilXml = new XmlUtil();
          String xmlFather = utilXml.textBetweenXmlTags(xml, SUBOBJETOS[0]);
          String xmlMother = utilXml.textBetweenXmlTags(xml, SUBOBJETOS[1]);
          String xmlBrothers = utilXml.textBetweenMultipleXmlTags(xml, SUBOBJETOS[2]);
          String xmlEducation = utilXml.textBetweenXmlTags(xml, SUBOBJETOS[3]);
          if (!xmlFather.equals("")){
               this.setFather(new Father(xmlFather));
          if (!xmlMother.equals("")){
               this.setMother(new Father(xmlMother));
          if (!xmlBrothers.equals("")){
            ArrayList aux = new ArrayList();
            String xmlBrother;
            while xmlBrothers != null && !xmlBrothers.equals("")){
              xmlBrother = utilXml.textBetweenXmlTags(xmlBrothers, SUBOBJETOS[2]);
              aux.add(new Brother(xmlBrother);
              xmlBrothers = utilXml.removeTagTreated(xmlBrothers, SUBOBJETOS[2]);
            this.setBrothers(aux);
          if (!xmlEducation.equals("")){
               this.setEducation(new Father(xmlEducation));
}If the object is a leaf object, the constructor will be like this:
public class Mother {
     //Elements
     private String name;
     private String age;
     public Mother(String xml){
          XmlUtil utilXml = new XmlUtil();
          HashMap objects = utilXml.parsearString(xml);
          ArraysList objectsList = new ArrayList();
          String[] Object = new String[2];
          this.setName((String)objects.get("Mother"));
          if (objects.get("attributes")!= null){
               objectsList = objects.get("attributes");
               for (int i = 0; i < objectsList.size();i++){
                 Object = objectsList.get(i);
                 if (object[0].equals("age"))
                   this.setAge(object[1]);
                 else
     }Each class will have its getter and setter but I do not have implemented in the examples.
Finally, the parser is as follows:
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import org.w3c.dom.Document;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.xml.sax.SAXException;
public class XmlUtil {
     public HashMap parsearString(String contenido){
          HashMap objet = new HashMap();
          DocumentBuilderFactory factory;
          DocumentBuilder builder;
          Document document;
          try{
               if (content != null && !content.equals("")){
                    factory = DocumentBuilderFactory.newInstance();
                    builder = factory.newDocumentBuilder();
                    document = builder.parse(new ByteArrayInputStream(content.getBytes()));
                    object = visitNodes(document);
               }else{
                    object = null;
          } catch (ParserConfigurationException e) {
               e.printStackTrace();
               return null;
          } catch (SAXException e) {
               e.printStackTrace();
               return null;
          } catch (IOException e) {
               e.printStackTrace();
               return null;
          return object;
     private HashMap visitNodes (Node node){
          String nodeName = "";
          String nodeValue = "";
          ArrayList attributes = new ArrayList();
          HashMap object = new HashMap();
          Node childNode = node.getFirstChild();
          if (childNode.getNodeType() == Node.ELEMENT_NODE){
               nodeName = childNode.getNodeName();
               if (childNode.hasAttributes()){
                    attributes = visitAttributes(childNode.getAttributes());
               }else{
                    attributes = null;
               nodeValue = getNodeValue(childNode);
               object.put(nodeName, nodeValue);
               object.put("attributes", attributes);
          return object;
     private static String getNodeValue (Node node){
          if (node.hasChildNodes() && node.getFirstChild().getNodeType() == Node.TEXT_NODE && !node.getFirstChild().getNodeValue().contains("\n\t"))
               return node.getFirstChild().getNodeValue();
          else
               return "";
     private ArrayList visitAttributes(NamedNodeMap attributes){
          Node node;
          ArrayList ListAttributes = new ArrayList();
          String [] attribute = new String[2];
          for(int i = 0; i < attributes.getLength(); i++){
               atribute = new String[2];
               node = attributes.item(i);
               if (node.getNodeType() == Node.ATTRIBUTE_NODE){
                    attribute[0] = node.getNodeName();
                    attribute[1] = node.getNodeValue();
                    ListAttributes.add(attribute);
          return ListAttributes;
}This code functioning properly. However, as exist around 400 objects to the xml, I wanted to create a method for more easily invoking objects that are below other and that's what I can't get to do at the moment.
The code I use is:
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
public class UtilClasses {
     public Object UtilClasses(String package, String object, String xml){
          try {
            Class class = Class.forName(package + "." + object);
            //parameter types for methods
            Class[] partypes = new Class[]{Object.class};
            //Create method object . methodname and parameter types
            Method meth = class.getMethod(object, partypes);
            //parameter types for constructor
            Class[] constrpartypes = new Class[]{String.class};
            //Create constructor object . parameter types
            Constructor constr = claseObjeto.getConstructor(constrpartypes);
            //create instance
            Object obj = constr.newInstance(new String[]{xml});
            //Arguments to be passed into method
            Object[] arglist = new Object[]{xml};
            //invoke method!!
            String output = (String) meth.invoke(dummyto, arglist);
            System.out.println(output);
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SecurityException e) {
            e.printStackTrace();
        } catch (NoSuchMethodException e) {
            e.printStackTrace();
        } catch (IllegalArgumentException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        } catch (InstantiationException e) {
            e.printStackTrace();
          return null;
     }This is an example obtained from the Internet that I've wanted modified to my needs. The problem is that when the class calls this method to invoke the constructor and does not fail, this does not do what I expect, because it creates an empty constructor. If not, the parent class gives a casting error.
I hope that now have been more clear my intentions and that no one has fallen asleep reading this lengthy explanation.
greetings.

Saving java objects without serialization

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