public class pr26390 { public interface ComponentPeer { public void setBounds(); } public interface ContainerPeer extends ComponentPeer { } public interface WindowPeer extends ContainerPeer { } public interface FramePeer extends WindowPeer { } public static class SwingComponentPeer implements ComponentPeer { public void setBounds() { } } public static class SwingContainerPeer extends SwingComponentPeer implements ContainerPeer { } public static class SwingWindowPeer extends SwingContainerPeer implements WindowPeer { } public static class SwingFramePeer extends SwingWindowPeer implements FramePeer { public void setBounds() { super.setBounds(); } } public static void main(String[] args) { SwingFramePeer s = new SwingFramePeer(); s.setBounds(); } }