this is a code for an input window that takes in data from users i tried to save whatever data the user put in in axml file but it is giving me errors...what is wrong with it...help

/*
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 * and open the template in the editor.
 */
package notifyme;

/**
 *
 * @author hermela
 */
import java.awt.Container;
import java.awt.FlowLayout;
import java.awt.GridLayout;
import java.awt.event.*;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;
import java.util.Hashtable;
import java.util.Vector;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.DefaultComboBoxModel;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JScrollPane;
import javax.swing.JSpinner;
import javax.swing.JTextArea;
import javax.swing.JTextField;
import javax.swing.SpinnerDateModel;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;



public class InputWindow extends JFrame {

    static Container pane;
    private JLabel EQUIPMENT;
    private JLabel Location;
    private JLabel DATE;
    private JLabel TIME, TYPE, space, space1;
    private JButton enter = new JButton("Enter");
    JButton compareBtn = new JButton("Comapre");
    private JComboBox location1, equipment1, type1;
    private Hashtable<Object, Object> subItems = new Hashtable<Object, Object>();
    private JTextField time;
    JTextArea xmlfileData;
    private JSpinner jSpinner1;
    //private java.text.SimpleDateFormat tf;
    DateComboBox dcb = new DateComboBox();
    private static String[] Lnames = {"SelectOne", "Addis Ababa", "Dire Dawa", "Mekelle", "Arbaminch", "Gode", "Gore", "Gawassa"};
    private static String[] Elist = {
        "SelectOne", "COMMUNICATION", "NAVIGATION", "SURVEILLANCE"};
    private static String[] Clist = {
        "SelectCommEqui", "VHF121.9", "VHF118.1", "125.1", "125.2", "VSAT"};
    private static String[] Nlist = {
        "SelectNavEqui", "VOR", "DME", "ILS", "DVOR", "GP", "AB Beacon", "BL Beacon"};
    private static String[] Slist = {
        "SelectSurveillanceEqui", "PSR", "SSR", "ADS-B",};
    SpinnerDateModel sm;

    public static void main(String args[]) {
        try {
            InputWindow iw = new InputWindow();
            iw.setSize(400, 400);
        } catch (ParseException ex) {
            Logger.getLogger(InputWindow.class.getName()).log(Level.SEVERE, null, ex);
        }

    }

    public InputWindow() throws ParseException {
        super("Notification Input Window");
        setLayout(new FlowLayout());
        final Container pane = getContentPane();
        pane.setLayout(new GridLayout(8, 8));

        EQUIPMENT = new JLabel("EQUIPMENT");
        TYPE = new JLabel("TYPE");
        equipment1 = new JComboBox(Elist);
        SelectType st = new SelectType();
        equipment1.addActionListener(st);
        //equipment1.addItemListener(this);
        type1 = new JComboBox();
        //type.addItemListener(this);
        String[] subItems1 = {
            "SelectCommEqui", "VHF121.9", "VHF118.1", "125.1", "125.2", "VSAT"};
        subItems.put(Elist[1], subItems1);
        String[] subItems2 = {
            "SelectNavEqui", "VOR", "DME", "ILS", "DVOR", "GP", "AB Beacon", "BL Beacon"};
        subItems.put(Elist[2], subItems2);
        String[] subItems3 = {
            "SelectSurveillanceEqui", "PSR", "SSR", "ADS-B",};
        subItems.put(Elist[3], subItems3);
//      mainComboBox.setSelectedIndex(1);

        Location = new JLabel("LOCATION");
        location1 = new JComboBox(Lnames);
        DATE = new JLabel("DATE");
        TIME = new JLabel("TIME");
        time = new JTextField();
        Date date = new Date();
        sm = new SpinnerDateModel(date, null, null, Calendar.HOUR_OF_DAY);
        jSpinner1 = new javax.swing.JSpinner(sm);
        JSpinner.DateEditor de = new JSpinner.DateEditor(jSpinner1, "HH:mm:ss");
        jSpinner1.setEditor(de);
        clickEnter enter1 = new clickEnter();
        enter.addActionListener(enter1);
        space = new JLabel();
        space1 = new JLabel();
        xmlfileData = new JTextArea();
        //     enter = new JButton("ENTER");

        pane.add(EQUIPMENT);
        pane.add(equipment1);
        pane.add(TYPE);
        pane.add(type1);
        pane.add(Location);
        pane.add(location1);
        pane.add(DATE);
        pane.add(dcb);
        pane.add(TIME);
        pane.add(jSpinner1);
        //pane.add(time);
        pane.add(space);
        pane.add(space1);
        pane.add(enter);
        pane.add(compareBtn);
        pane.add( new JScrollPane(   xmlfileData));
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setSize(1700, 1200);
        setVisible(true);
        compareBtn.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e) {
                xMLData.compare();
            }
        });

        equipment1.addItemListener(itemListener);
        type1.addItemListener(itemListener);
        location1.addItemListener(itemListener);
        dcb.addItemListener(itemListener);
        sm.addChangeListener(new ChangeListener() {

            @Override
            public void stateChanged(ChangeEvent e) {
                xMLData.compare();
            }
        });

    }

    ItemListener itemListener = new ItemListener() {

        @Override
        public void itemStateChanged(ItemEvent e) {
            xMLData.compare();
        }
    };

    class SelectType implements ActionListener {

        @Override
        public void actionPerformed(ActionEvent e) {
            String item = (String) equipment1.getSelectedItem();
            Object o = subItems.get(item);
            if (o == null) {
                type1.setModel(new DefaultComboBoxModel());
            } else {
                type1.setModel(new DefaultComboBoxModel((String[]) o));
            }
        }
    }

    class clickEnter implements ActionListener {

        @Override
        public void actionPerformed(ActionEvent e) {
            try {
                xMLData.saveDataFile();
                xMLData.loadXMLData();
                //FileOutputStream  fos = new FileOutputStream(null);
            } catch (Exception ex) {
                ex.printStackTrace();
            }
        }
    }
    XMLData xMLData = new XMLData();

    final class XMLData {

        ArrayList<Data> data = new ArrayList<>();

        public XMLData() {
            loadXMLData();
        }

        void loadXMLData() {

            try {
                DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
                DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();

                File dir = new File("C:\\Users\\shady\\Documents\\NetBeansProjects\\NotifyMe\\xmldata");
                File xmlFile[] = dir.listFiles();
                for (int i = 0; i < xmlFile.length; i++) {
                    Document doc = dBuilder.parse(xmlFile[i]);
                    doc.getDocumentElement().normalize();
                    NodeList nList = doc.getElementsByTagName("data");
                 //   System.out.println(nList.getLength());
                    for (int j = 0; j < nList.getLength(); j++) {
                        Node node = nList.item(j);
                        NodeList nl = node.getChildNodes();

                        String eqp = nl.item(1).getTextContent();
                        String type = nl.item(3).getTextContent();
                        String loc = nl.item(5).getTextContent();
                        String date = nl.item(7).getTextContent();
                        String time = nl.item(9).getTextContent();
                        Data d = new Data(eqp, type, loc, date, time);
                        data.add(d);
                       // System.out.println(d);
                    }
                }
            } catch (ParserConfigurationException ex) {
                ex.printStackTrace();
            } catch (SAXException ex) {
                ex.printStackTrace();
            } catch (IOException ex) {
                ex.printStackTrace();
            }
        }

        void saveDataFile() {

            try {

              //  System.out.println(sm.getValue());
               // System.out.println(sm.getDate());
                SimpleDateFormat sdf = new SimpleDateFormat("MMM dd,yyyy");
               // System.out.println(dcb.getSelectedItem());

                Date ndt = sdf.parse(dcb.getSelectedItem().toString());
               // System.out.println(ndt);
                SimpleDateFormat nsdt = new SimpleDateFormat("MM/dd/yyyy");
                String nndt = nsdt.format(ndt);
               // System.out.println(nndt);
                SimpleDateFormat sdft = new SimpleDateFormat("HH:mm");
            //    System.out.println(sdft.format(sm.getDate()));

//
//                String name = equipment1.getSelectedItem().toString() + "_" + type1.getSelectedItem().toString()
//                        + "_" + location1.getSelectedItem().toString() + "_" + df + ".xml";
                String name = "c:\\xmldata\\xmlData.xml";
                byte byteData[];
                File f = new File(name);
                if (f.exists()) {
//                    FileInputStream fis = new FileInputStream(name);
//                    byteData = new byte[fis.available()];
//                    fis.read(byteData);
//                    fis.close();
//                    
                    FileOutputStream fos = new FileOutputStream(name);
////                    fos.write(byteData, 0, byteData.length);
////                    fos.flush();
////                    byte[] newXml = generateXML(false).getBytes();
////                    fos.write(newXml, 0, newXml.length);
////                    fos.flush();
////                    fos.close();
                    byte b[] = new String("<?xml version=\"1.0\"?>\n").getBytes();
                    fos.write(b, 0, b.length);
                    fos.flush();
                    byte b1[] = "<root>".getBytes();
                    fos.write(b1, 0, b1.length);
                    fos.flush();
                    for (int i = 0; i < data.size(); i++) {
                        String dd = null;
                        dd = generateXML(data.get(i));
                        fos.write(dd.getBytes());
                        fos.flush();
                    }
                    String dd = generateXML();
                    fos.write(dd.getBytes());
                    fos.write("</root>".getBytes());
                    fos.flush();
                    fos.close();

                } else {
                    FileOutputStream fos = new FileOutputStream(name);
                    byte b[] = new String("<?xml version=\"1.0\"?>\n").getBytes();
                    fos.write(b, 0, b.length);
                    fos.flush();
                    byte b1[] = "<root>".getBytes();
                    fos.write(b1, 0, b1.length);
                    fos.flush();
                 //   System.out.println("root call");
                    byte[] newXml = generateXML().getBytes();
                    fos.write(newXml, 0, newXml.length);
                    fos.write("</root>".getBytes());
                    fos.flush();

                    fos.close();
                }

//                File file=new File(name);
//                file.createNewFile();
//                FileOutputStream fos = new FileOutputStream(file);
//                byte by[]=generateXML(df).getBytes();
//                fos.write(by,0,by.length);
//                fos.flush();
//                fos.close();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }

        private String generateXML() {
            StringBuilder sb = new StringBuilder();

            //sb.append("<?xml version=\"1.0\"?>");
            sb.append("\n<data>\n");
            sb.append("<equipment>" + equipment1.getSelectedItem().toString() + "</equipment>\n");
            sb.append("<type>" + type1.getSelectedItem().toString() + "</type>\n");
            sb.append("<location>" + location1.getSelectedItem().toString() + "</location>\n");
            sb.append("<date>" + getDate() + "</date>\n");
            sb.append("<time>" + getTime() + "</time>\n");
            sb.append("</data>");
            String st = sb.toString();
            // System.out.println(st);
            return st;
        }

        private String generateXML(Data d) {
            StringBuilder sb = new StringBuilder();

            sb.append("\n<data>\n");
            sb.append("<equipment>" + d.getEquipment() + "</equipment>\n");
            sb.append("<type>" + d.getType() + "</type>\n");
            sb.append("<location>" + d.getLocation() + "</location>\n");
            sb.append("<date>" + d.getDate() + "</date>\n");
            sb.append("<time>" + d.getTime() + "</time>\n");
            sb.append("</data>");
            String st = sb.toString();
            //System.out.println(st);
            return st;
        }

        String getDate() {
            String date = null;
            try {
                SimpleDateFormat sdf = new SimpleDateFormat("MMM dd,yyyy");
             //   System.out.println(dcb.getSelectedItem());

                Date ndt = sdf.parse(dcb.getSelectedItem().toString());

                SimpleDateFormat nsdt = new SimpleDateFormat("MM/dd/yyyy");
                date = nsdt.format(ndt);
                //   System.out.println(date);
            } catch (Exception e) {
                //e.printStackTrace();
            }
            return date;
        }

        String getTime() {
            String time = null;
            try {
                SimpleDateFormat sdft = new SimpleDateFormat("HH:mm");
                time = sdft.format(sm.getDate());
                //System.out.println(time);
            } catch (Exception e) {
                //e.printStackTrace();;
            }
            return time;
        }

        void compare() {
            try {
                Data curentData = new Data(
                        equipment1.getSelectedItem().toString(),
                        type1.getSelectedItem().toString(),
                        location1.getSelectedItem().toString(), getDate(), getTime());
              //  System.out.println(data.size());
                for (int i = 0; i < data.size(); i++) {
                    //System.out.println(data.get(i));
                    if (data.get(i).equals(curentData)) {
                        xmlfileData.setText(generateXML());
                    }
                }
            } catch (Exception e) {

            }
        }

    }
}

it is giving me errors ... Personally, I'm surprised about that, seeing that you have code like:

catch (Exception e) {
            }

at least three times.

Can you please be more specific as to what errors you encounter? compile time? run time? wrong output?

this is the error i get....

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
    at notifyme.InputWindow$XMLData.loadXMLData(InputWindow.java:226)
    at notifyme.InputWindow$XMLData.<init>(InputWindow.java:215)
    at notifyme.InputWindow.<init>(InputWindow.java:208)

Check line 226 of your InputWindow class. it seems you have a NPE occuring there. Might be caused by one of those try-catch where you hide the Exception, so print those stacktraces as well, just to be sure you have all the facts.