How do I rewrite current code for java 1.3

Question

I'm using the code below that is written for java 1.4. I have been told that the company can not push JRE 1.4 to the company, and that I need to write my code for java 1.3. I'm using org.w3c.dom for my create xml, etc.
Is there a java 1.3 option to the 1.4? Any help would be very appreciated.
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import java.util.List;
import java.io.*;
import java.util.*;
import javax.xml.parsers.*;
import javax.xml.transform.*;
import javax.xml.transform.dom.*;
import javax.xml.transform.stream.*;
import org.w3c.dom.*;
public class Sametime extends JFrame implements ActionListener {
    private int indentation = -1;
    JPanel panel = new JPanel();
    JTextArea jta = new JTextArea(
    //Instructions for user
    "For a successful buddy list migration do the following:\n"
    + "1. Save your current Sametime Buddy List to your PC.\n   "
    + "The default location should be: C:/Program Files/Lotus/Sametime Client.\n"
    + "  A. Open the Sametime Client.\n"
    + "  B. Click on People\n"
    + "  C. Click on Save List.\n"
    + "  D. Save as your first.last.dat\n"
    + "     Ex. john.doe.dat\n"
    + "NOTE: If you have AOL contacts in your Sametime buddy list they will not be migrated.\n");
    JButton browse = new JButton("Continue");
    JButton exit = new JButton("Exit");
    public Sametime() {
        super("Sametime Buddy List Migration");
        setSize(610, 245);
        Container c = this.getContentPane();
        c.add(panel);
        browse.addActionListener(this);
        exit.addActionListener(this);
        panel.add(jta);
        panel.add(browse);
        panel.add(exit);
        jta.setEditable(false);
        setLookAndFeel();
        setVisible(true);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    } //end Sametime
    public class DATFilter extends javax.swing.filechooser.FileFilter {
        public boolean accept(File f) {
            //if it is a directory -- we want to show it so return true.
            if (f.isDirectory())
                return true;
            String extension = getExtension(f);//get the extension of the file
            //check to see if the extension is equal to "dat"
            if ((extension.equals("dat")))
                return true;
            //default -- fall through. False is return on all
            //occasions except:
            //a) the file is a directory
            //b) the file's extension is what we are looking for.
            return false;
        }//end accept
        public String getDescription() {
            return "dat files";
        }//end getDescription
         * Method to get the extension of the file, in lowercase
        private String getExtension(File f) {
            String s = f.getName();
            int i = s.lastIndexOf('.');
            if (i > 0 &&  i < s.length() - 1)
                return s.substring(i+1).toLowerCase();
            return "";
        }//end getExtension
    }//end class DATFilter
    public void actionPerformed(ActionEvent e) {
        //Default Location for JFileChooser search
        String error = "The file selected is not a .dat file!\n"
        + "Please select your recently saved .dat file and try again.";
        JFileChooser fc = new JFileChooser("/Program Files/Lotus/Sametime Client");
        fc.setFileFilter(new DATFilter());
        fc.setFileSelectionMode( JFileChooser.FILES_ONLY);
        String user = System.getProperty("user.name");// finds who the current user is
        if (e.getSource() == browse) {
            int returnVal = fc.showSaveDialog(Sametime.this);
            if (returnVal == JFileChooser.APPROVE_OPTION) {
                //if (fc.getSelectedFile().getName().equals(".dat")){
                if (fc.getSelectedFile().getName().endsWith(".dat")){ // checks to see if selected file is .dat
                }else{
                    JOptionPane.showMessageDialog(null, error, "Wrong File", JOptionPane.ERROR_MESSAGE);
                    return;
                }//end else
                try {
                    String[] contactArray = parseDatFile(fc.getSelectedFile());
                    Document document = createXMLDocument(contactArray);
                    saveToXMLFile(
                    document,
                    new File(
                    "C:/Documents and Settings/" + user +"/My Documents/OLCS/",// looks for directory for list
                    "contacts-list_migration.ctt"));
                } catch (Exception exc) {
                    File f = new File("C:/Documents and Settings/" + user +"/My Documents/OLCS/");// setting directory for list if not there
                    boolean yes = true;
                    yes = f.mkdir();// creating directory
                    try {
                        String[] contactArray = parseDatFile(fc.getSelectedFile());
                        Document document = createXMLDocument(contactArray);
                        saveToXMLFile(
                        document,
                        new File(
                        "C:/Documents and Settings/" + user +"/My Documents/OLCS/",// used only if the directory didn't exist
                        "contacts-list_migration.ctt"));
                        //exc.printStackTrace();// not sure if this is needed?
                    } catch (Exception exc1) {
                        exc1.printStackTrace();
                    }//end inner catch
                }// end catch
            }// end if
            if(returnVal==JFileChooser.CANCEL_OPTION){
                String Warning = "You did not migrate your Sametime buddy list at this time.";
                JOptionPane.showMessageDialog(null, Warning, "Migration Canceled", JOptionPane.WARNING_MESSAGE);
                return;
            }else{
                String thankyou = "Thank You for Migrating your Sametime buddy list to OLCS"
                + "\nYour new OLCS buddy list has been saved to:"
                + "\nC:/Documents and Settings/" + user +"/My Documents/OLCS"
                + "\n as: Contact-List_migration.ctt"
                + "\n\n To be able to use Contact-List_migration.ctt for Windows Messenger:"
                + "\n1. Log into Windows Messenger."
                + "\n2. Click on File"
                + "\n3. Click on 'Import Contacts from a Saved File...'"
                + "\n4. Open OLCS in My Documents"
                + "\n5. Click on 'Contact-list_migration.ctt'"
                + "\n6. Click Open to import the list."
                + "\n   A window will pop up confirming that you want to add all of the contacts"
                + "\n   Click 'yes'"
                + "\n   Your buddy list is ready to be used.";
                JOptionPane.showMessageDialog(null, thankyou, "Migration Completed", JOptionPane.INFORMATION_MESSAGE);//Change this when defualt directory is known.
            }//end if else statement
        } //end if
        System.exit( 0 );
        if (e.getSource() == exit) {
            System.exit( 0 );
        } //end if
    } //end actionPerformed
    String[] parseDatFile(File datFile)
    throws Exception    {
        List list = new ArrayList();
        BufferedReader br = new BufferedReader(new FileReader(datFile));
        String line;
        while ((line = br.readLine()) != null) {
            line = line.trim();
            if (line.indexOf("U") != 0)
                continue;
            int p = line.indexOf("::");
            if (p == -1)
                continue;
            line = line.substring(p + 2).trim();
            if (line.indexOf("AOL") == 0)
                continue;
            p = line.indexOf(",");
            if (p != -1)
                line = line.substring(0, p);
            line = line.trim() + "@mci.com";
            if (list.indexOf(line) == -1)
                list.add(line);
        }//end while
        br.close();
        String[] contactArray = new String[list.size()];
        list.toArray(contactArray);
        return contactArray;
    }// end String
    // setting up the XML file
    Document createXMLDocument(String[] contactArray) throws Exception {
        DocumentBuilderFactory dBF = DocumentBuilderFactory.newInstance();
        DocumentBuilder builder = dBF.newDocumentBuilder();
        DOMImplementation domImpl = builder.getDOMImplementation();
        Document document = domImpl.createDocument(null, "messenger", null);
        Element root = document.getDocumentElement();
        Element svcElm = document.createElement("service");
        Element clElm = document.createElement("contactlist");
        svcElm.setAttribute("name", "Microsoft RTC Instant Messaging");
        svcElm.appendChild(clElm);
        root.appendChild(svcElm);
        for (int i = 0; i < contactArray.length; i++) {
            Element conElm = document.createElement("contact");
            Text conTxt = document.createTextNode(contactArray);
conElm.appendChild(conTxt);
clElm.appendChild(conElm);
}//end for
return document;
}// end Document
void saveToXMLFile(Document document, File xmlFile) throws Exception {
OutputStream os =
new BufferedOutputStream(new FileOutputStream(xmlFile));
TransformerFactory tFactory = TransformerFactory.newInstance();
Transformer transformer = tFactory.newTransformer();
transformer.setOutputProperty(OutputKeys.INDENT, "yes");//puts information on seperate lines
transformer.setOutputProperty(OutputKeys.METHOD, "xml");
transformer.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "2");//gives the XML file indentation
transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "no");
DOMSource source = new DOMSource(document);
StreamResult result = new StreamResult(os);
transformer.transform(source, result);
os.close();
}//end saveToXMLFile
public static void main(String[] args) {
Sametime st = new Sametime();
ImageIcon picIcon = new ImageIcon(st.getClass().getResource("/images/mci.gif"));//Change when default is known!
st.setIconImage(picIcon.getImage());
} //end main
private void setLookAndFeel() {
try {
UIManager.setLookAndFeel(
UIManager.getSystemLookAndFeelClassName());
SwingUtilities.updateComponentTreeUI(this);
} catch (Exception e) {
System.err.println("Could not use Look and Feel: " + e);
} //end catch
} //end void setLookAndFeel
} //end public class Sametime

Answer 1

Are there features of Java 1.4 that you specifically took advantage and are there any particular lines you are having problems with or did you just freak and post it here?
Basically compile it under Java 1.3 and see what complains. I've done several projects that compile under 1.2, 1.3, and 1.4.