I need help with my program

Well my program is supposed to compress files that are choosen by the user but I always get this one error with my array that I am using:

Code:

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java.lang.ArrayIndexOutOfBoundsException: 0
        at azipper.azipperWindow.calculateStringArray(azipperWindow.java:197)
        at azipper.azipperWindow.jButton4ActionPerformed(azipperWindow.java:220)
        at azipper.azipperWindow.access$200(azipperWindow.java:21)
        at azipper.azipperWindow$3.actionPerformed(azipperWindow.java:78)
        at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1995)
        at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2318)
        at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:387)
        at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:242)
        at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:236)
        at java.awt.Component.processMouseEvent(Component.java:6267)
        at javax.swing.JComponent.processMouseEvent(JComponent.java:3267)
        at java.awt.Component.processEvent(Component.java:6032)
        at java.awt.Container.processEvent(Container.java:2041)
        at java.awt.Component.dispatchEventImpl(Component.java:4630)
        at java.awt.Container.dispatchEventImpl(Container.java:2099)
        at java.awt.Component.dispatchEvent(Component.java:4460)
        at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4577)
        at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4238)
        at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4168)
        at java.awt.Container.dispatchEventImpl(Container.java:2085)
        at java.awt.Window.dispatchEventImpl(Window.java:2478)
        at java.awt.Component.dispatchEvent(Component.java:4460)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)

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Here is my code:

Code:

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/*
 * azipperWindow.java
 *
 * Created on Jan 21, 2011, 7:56:24 PM
 */

package azipper;
import java.io.File;
import javax.swing.*;
import java.io.*;
import java.util.zip.*;



/**
 *
 * @author Andrew Delgadillo
 */
public class azipperWindow extends javax.swing.JFrame {

    DefaultListModel model = new DefaultListModel();
 
   

    /** Creates new form azipperWindow */
    public azipperWindow() {
        initComponents();
       
       
    }

    /** This method is called from within the constructor to
    * initialize the form.
    * WARNING: Do NOT modify this code. The content of this method is
    * always regenerated by the Form Editor.
    */
    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">                         
    private void initComponents() {

        jButton1 = new javax.swing.JButton();
        jButton2 = new javax.swing.JButton();
        jLabel1 = new javax.swing.JLabel();
        jButton4 = new javax.swing.JButton();
        jSeparator1 = new javax.swing.JSeparator();
        jLabel2 = new javax.swing.JLabel();
        jButton5 = new javax.swing.JButton();
        jScrollPane1 = new javax.swing.JScrollPane();
        jList1 = new javax.swing.JList();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
        setTitle("A-Zipper ");
        setName("mainWindow"); // NOI18N

        jButton1.setText("Add File");
        jButton1.setName("addFile"); // NOI18N
        jButton1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton1ActionPerformed(evt);
            }
        });

        jButton2.setText("Delete File");
        jButton2.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton2ActionPerformed(evt);
            }
        });

        jLabel1.setText("Compress File(s)");

        jButton4.setText("Compress File(s)");
        jButton4.setName("compress"); // NOI18N
        jButton4.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton4ActionPerformed(evt);
            }
        });

        jLabel2.setText("Uncompress File");

        jButton5.setText("Decompress File");
        jButton5.setName("compress"); // NOI18N

        jScrollPane1.setViewportView(jList1);

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
                    .addComponent(jLabel1)
                    .addComponent(jButton2, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                    .addComponent(jButton4, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                    .addComponent(jButton1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
                .addGap(18, 18, 18)
                .addComponent(jScrollPane1, javax.swing.GroupLayout.DEFAULT_SIZE, 277, Short.MAX_VALUE)
                .addContainerGap())
            .addComponent(jSeparator1, javax.swing.GroupLayout.DEFAULT_SIZE, 426, Short.MAX_VALUE)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addComponent(jLabel2)
                .addContainerGap(339, Short.MAX_VALUE))
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addComponent(jButton5)
                .addContainerGap(307, Short.MAX_VALUE))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
                    .addGroup(layout.createSequentialGroup()
                        .addComponent(jLabel1)
                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                        .addComponent(jButton1)
                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                        .addComponent(jButton2)
                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                        .addComponent(jButton4))
                    .addComponent(jScrollPane1, 0, 0, Short.MAX_VALUE))
                .addGap(18, 18, 18)
                .addComponent(jSeparator1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addComponent(jLabel2)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addComponent(jButton5)
                .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
        );

        jButton2.getAccessibleContext().setAccessibleName("");

        pack();
    }// </editor-fold>                       

    private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                       
     
        jList1.setModel(model);

        final JFileChooser fc = new JFileChooser();
        fc.setMultiSelectionEnabled(false);

        int returnVal = fc.showOpenDialog(azipperWindow.this);





        if (returnVal == JFileChooser.APPROVE_OPTION) {
            File file = fc.getSelectedFile();

            model.addElement(file.getAbsolutePath());
         
           



           

         
           
           

        }


    }                                       

    private void jButton2ActionPerformed(java.awt.event.ActionEvent evt) {                                       
        int index = jList1.getSelectedIndex();
             
        if(index != -1) {
        model.remove(index);

        }
           

       




    }                                       


    private String[] calculateStringArray() {
      int size = ((model.getSize()) - 1);
       
        String files[] = new String[size];

        for(int i = 0; i < model.getSize(); i++) {
            files[i] = String.valueOf(model.get(i));

        }

        return files;
    }
    private void jButton4ActionPerformed(java.awt.event.ActionEvent evt) {                                       
    JFileChooser cf = new JFileChooser();
    cf.setDialogTitle("Choose where to save archive...");
   
    int returnvalue = cf.showDialog(null, "Save Archive");
    File zip = cf.getSelectedFile();
        if(returnvalue == JFileChooser.APPROVE_OPTION) {
            final int BUFFER = 2048;
            try {
        BufferedInputStream origin = null;
        FileOutputStream dest = new
          FileOutputStream(zip.getAbsolutePath()+".zip");
        ZipOutputStream out = new ZipOutputStream(new
          BufferedOutputStream(dest));
        //out.setMethod(ZipOutputStream.DEFLATED);
        byte data[] = new byte[BUFFER];
        // get a list of files from current directory
        String[] files = calculateStringArray();
       
       
       

        for (int i=0; i<files.length; i++) {
           
            FileInputStream fi = new
              FileInputStream(files[i]);
            origin = new
              BufferedInputStream(fi, BUFFER);
            ZipEntry entry = new ZipEntry(files[i]);
            out.putNextEntry(entry);
            int count;
            while((count = origin.read(data, 0,
              BUFFER)) != -1) {
              out.write(data, 0, count);
            }
            origin.close();
        }
        out.close();
      } catch(Exception e) {
        e.printStackTrace();
      }

           
        }




    }                                       




    /**
    * @param args the command line arguments
    */
    public static void main(String args[]) {
        try {
           
        UIManager.setLookAndFeel(
            UIManager.getSystemLookAndFeelClassName());
    }
    catch (UnsupportedLookAndFeelException e) {
      JOptionPane.showMessageDialog(null, "Error");
    }
    catch (ClassNotFoundException e) {
      JOptionPane.showMessageDialog(null, "Error");
    }
    catch (InstantiationException e) {
      JOptionPane.showMessageDialog(null, "Error");
    }
    catch (IllegalAccessException e) {
      JOptionPane.showMessageDialog(null, "Error");
    }

        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new azipperWindow().setVisible(true);
               
            }
        });

   
    }

    // Variables declaration - do not modify                   
    private javax.swing.JButton jButton1;
    private javax.swing.JButton jButton2;
    private javax.swing.JButton jButton4;
    private javax.swing.JButton jButton5;
    private javax.swing.JLabel jLabel1;
    private javax.swing.JLabel jLabel2;
    private javax.swing.JList jList1;
    private javax.swing.JScrollPane jScrollPane1;
    private javax.swing.JSeparator jSeparator1;
    // End of variables declaration                 



}

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My problem is when I press the compress files button it always gives me a array out of bounds expetion what should I do to fix this?

Code:

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private String[] calculateStringArray() {
    int size = ((model.getSize()) - 1);
       
    String files[] = new String[size];

    for(int i = 0; i < model.getSize(); i++) {
        files[i] = String.valueOf(model.get(i));

    }

    return files;
}

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This code sets up an array with model.getSize()-1 places in it. But then you use a for loop that will access up to model.getSize() places. Basically you should make the array larger:

Code:

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int size = model.getSize();
String files[] = new String[size];

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Thanks that fixed the problem, I would have never suspected it, I am pretty new to java and it is just a hobby. Could I ask another question? When I debug it and press the compress files button it creates a .zip file but it has nothing in it. I followed the tutorials that is on oracle.com. I just don't know what is wrong with it!

You're welcome. You'll quickly get used to the fact than an array declared as new Whatever[n] has index values that run from 0 to n-1. Therefore the appropriate for loop would be for(int i=0; i<n; i++).

As regards the file not having any content... I have run your program a few times and noticed that although WindowsExplorer showed no contents the .zip files were different sizes. Choosing "Extract All..." from the File menu brought up (eventually) a "Windows has blocked access to these files" message.

Anyway the .zip files opened OK using WinZip so I think the problem may lie with Windows faulty security rather than your program.

You might try checking the properties of the .zip file. If you see an "Unblock" option near the bottom, choose it.

Others may be able to provide better help here. I have seen this before, but can't remember the details.