Hello, I have a little problem with my java-program. I wanna use Observer, to synchronize two GUIs. But I can't synchronize the JComponent / JButton elements. For example: I have a GUI-Class which implements the Observer-Class: public class GUI extends JFrame implements Observer I have a second "GUI"-Class which extends the JButton-Class and makes changes on a specific Button-Element. public class Karte extends JButton{ ... this.setEnabled(false); ... How do I synchronize this Button via Observable? I have already tried to use "extends Observable" in this class, but the "setEnabled()" method is explicit for the JButton-Class, which is not Observable! Can someone help? Thanks.