Wrong current working directory

Hello, everybody!

I have an unusual problem with a simple Java application that lists the Java system properties. The user.dir or current working directory is different when I run the application in GNU/Linux compared to Windows XP. In GNU/Linux, if I run it from the command line, it displays the right user.dir. But, if I run it by double-clicking the JAR executable (created by NetBeans 7.0 IDE) it displays always user.dir as ~ (/root, /home/user etc.), regardless of the executable's location. But this doesn't happen in Windows XP, where the application displays the same thing, no matter the choice made. If I launch the application from within the IDE, it runs perfectly, on both systems.

The source-code is:

Code Java:

import javax.swing.*;
import java.util.*;
import java.io.*;
import java.awt.*;
 
class SystemProperties {
 
    private JFrame f;
    private JPanel p;
    private JTextArea ta;
    private JScrollPane sp;
 
    public static void main(String[] args) {
        new SystemProperties();
    }
 
    public SystemProperties() {
        f = new JFrame();
        p = new JPanel();
        ta = new JTextArea(21, 28);
        sp = new JScrollPane(ta);
        sp.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_AS_NEEDED);
        sp.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED);
        Properties props = System.getProperties();
        Enumeration enum1 = props.propertyNames();
        for (; enum1.hasMoreElements();) {
            String propName = (String) enum1.nextElement();
            String propValue = (String) props.get(propName);
            if (propName.equals("java.library.path")) {
                String[] libraryPath = propValue.split(":");
                int length = libraryPath.length;
                ta.append(propName + " = " + libraryPath[0] + "\n");
                for (int i = 1; i < length; i++) {
                    ta.append(libraryPath[i] + "\n");
                }
            }
            ta.append(propName + " = " + propValue + "\n");
        }
        File dir1 = new File(".");
        File dir2 = new File("..");
        try {
            ta.append("Current directory is " + dir1.getCanonicalPath() + "\n");
            ta.append("Parent directory is " + dir2.getCanonicalPath() + "\n");
        } catch (Exception e) {
        }
        ta.setEditable(false);
        p.add(sp);
        f.add(p);
        f.pack();
        f.setTitle("System properties");
        f.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        f.setSize(400, 400);
        Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
        f.setLocation((screenSize.width / 2 - f.getBounds().width / 2), (screenSize.height / 2 - f.getBounds().height / 2));
        f.setVisible(true);
    }
}