/* * GUIFactory example */abstract class GUIFactory {    public static GUIFactory getFactory () {        int sys = readFromConfigFile ("OS_TYPE") ;        if (sys == 0) {            return new WinFactory () ;        } else {            return new OSXFactory () ;        }    }    public abstract Button createButton () ;}class WinFactory extends GUIFactory {    public Button createButton () {        return new WinButton () ;    }}class OSXFactory extends GUIFactory {    public Button createButton () {        return new OSXButton () ;    }} abstract class Button {    public abstract void paint () ;}class WinButton extends Button {    public void paint () {        System.out.println ("I'm a WinButton") ;    }} class OSXButton extends Button {    public void paint () {        System.out.println ("I'm an OSXButton") ;    }} public class Application{    public static void main (String[] args) {        GUIFactory factory = GUIFactory.getFactory () ;        Button button = factory.createButton () ;        button.paint () ;    }    // Output is either:    //   "I'm a WinButton"    // or:    //   "I'm an OSXButton"}