How does one load a logical fonts physical font? (Making a JComboBox font chooser)

Followup question from this one: Swing font names do not match? (Making a font chooser, and am trying to display the开发者_开发知识库 default system font in a JComboBox)

It appears there are logical and physical fonts. The logical fonts are: Serif, SansSerif, Monospaced, Dialog, and DialogInput.

These fonts are dynamic, and their respective physical font (the font that they will represent during program execution) are decided when the program loads.

I need to access the physical font of these logical fonts.

My first idea was to try and load these files: http://download.oracle.com/javase/6/docs/technotes/guides/intl/fontconfig.html#loading

by using something like this: http://www.rgagnon.com/javadetails/java-0434.html

public static Properties load(String propsName) throws Exception {
    Properties props = new Properties();
    URL url = ClassLoader.getSystemResource(propsName);
    props.load(url.openStream());
    return props;
}

and then getting the physical fonts from these properties files.

However, I am just getting NullPointerExceptions when trying to load the properties using the names in the first file (they are not found, but I have checked and actually found them on my system). I don't know why I am getting this, but regardless of that, I can't help to think there must be an easier way to do this?

public static Font getPhysicalFont(Font logicalFont) {
    for (int i=0; i<FontManager.getRegisteredFonts().length; i++) {
        Font2D font = FontManager.getRegisteredFonts()[i];
        if (font instanceof CompositeFont && font.getFontName(Locale.getDefault()).equals(logicalFont.getFontName())) {
            PhysicalFont physicalFont = ((CompositeFont) font).getSlotFont(0);
            return new Font(physicalFont.getFamilyName(Locale.getDefault()), physicalFont.getStyle(), logicalFont.getSize());
        }
    }
    return logicalFont;
}