改变Java应用程序的外观

Question

我正在创建一个类似于Amazon网站的简单程序，试图了解有关GUI管理的更多信息。 这是我的问题：我希望用户可以更改应用程序的外观。 它运作良好，但是如果我将一个简单的JComboBox放入JPanel中，则效果不佳。 有什么具体原因吗？ 我试图添加一个空的组合框，但它不能像以前一样工作。

感谢帮助

class GUI_SearchPanel extends JPanel implements ActionListener{

private JComboBox categories = new JComboBox();

public GUI_SearchPanel() {
    add(categories);
}}

public class AppStyle extends JFrame implements ActionListener{

private JPanel jp = new JPanel();
private ButtonGroup bg = new ButtonGroup();

public AppStyle() {
    for(EnumStyle style : EnumStyle.values()) {
        JRadioButton jrb = new JRadioButton(style.toString());
        jrb.addActionListener(this);
        bg.add(jrb);
        jp.add(jrb);
    }
}

@Override
public void actionPerformed(ActionEvent e) {
    try {
        UIManager.setLookAndFeel("de.javasoft.plaf.synthetica.Synthetica" + ((JRadioButton)e.getSource()).getText() + "LookAndFeel");
        SwingUtilities.updateComponentTreeUI(this);
        pack();
    }
    catch (Exception exc) {
    }
}

}

堆栈跟踪：

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
    at javax.swing.plaf.synth.SynthComboBoxUI.paintCurrentValue(SynthComboBoxUI.java:379)
    at javax.swing.plaf.synth.SynthComboBoxUI.paint(SynthComboBoxUI.java:358)
    at javax.swing.plaf.synth.SynthComboBoxUI.update(SynthComboBoxUI.java:326)
    at javax.swing.JComponent.paintComponent(JComponent.java:777)
    at javax.swing.JComponent.paint(JComponent.java:1053)
    at javax.swing.JComponent.paintChildren(JComponent.java:886)
    at javax.swing.JComponent.paint(JComponent.java:1062)
    at javax.swing.JComponent.paintToOffscreen(JComponent.java:5217)
    at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(RepaintManager.java:1532)
    at javax.swing.RepaintManager$PaintManager.paint(RepaintManager.java:1455)
    at javax.swing.RepaintManager.paint(RepaintManager.java:1252)
    at javax.swing.JComponent._paintImmediately(JComponent.java:5165)
    at javax.swing.JComponent.paintImmediately(JComponent.java:4976)
    at javax.swing.RepaintManager$3.run(RepaintManager.java:811)
    at javax.swing.RepaintManager$3.run(RepaintManager.java:794)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75)
    at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:794)
    at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:769)
    at javax.swing.RepaintManager.prePaintDirtyRegions(RepaintManager.java:718)
    at javax.swing.RepaintManager.access$1100(RepaintManager.java:62)
    at javax.swing.RepaintManager$ProcessingRunnable.run(RepaintManager.java:1680)
    at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:311)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:744)
    at java.awt.EventQueue.access$400(EventQueue.java:97)
    at java.awt.EventQueue$3.run(EventQueue.java:697)
    at java.awt.EventQueue$3.run(EventQueue.java:691)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:714)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
    at javax.swing.plaf.synth.SynthComboBoxUI.paintCurrentValue(SynthComboBoxUI.java:379)
    at javax.swing.plaf.synth.SynthComboBoxUI.paint(SynthComboBoxUI.java:358)
    at javax.swing.plaf.synth.SynthComboBoxUI.update(SynthComboBoxUI.java:326)
    at javax.swing.JComponent.paintComponent(JComponent.java:777)
    at javax.swing.JComponent.paint(JComponent.java:1053)
    at javax.swing.JComponent.paintChildren(JComponent.java:886)
    at javax.swing.JComponent.paint(JComponent.java:1062)
    at javax.swing.JComponent.paintChildren(JComponent.java:886)
    at javax.swing.JComponent.paint(JComponent.java:1062)
    at javax.swing.JComponent.paintChildren(JComponent.java:886)
    at javax.swing.JComponent.paint(JComponent.java:1062)
    at javax.swing.JComponent.paintChildren(JComponent.java:886)
    at javax.swing.JComponent.paint(JComponent.java:1062)
    at javax.swing.JLayeredPane.paint(JLayeredPane.java:586)
    at javax.swing.JComponent.paintChildren(JComponent.java:886)
    at javax.swing.JComponent.paint(JComponent.java:1062)
    at javax.swing.JComponent.paintToOffscreen(JComponent.java:5217)
    at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(RepaintManager.java:1532)
    at javax.swing.RepaintManager$PaintManager.paint(RepaintManager.java:1455)
    at javax.swing.RepaintManager.paint(RepaintManager.java:1252)
    at javax.swing.JComponent._paintImmediately(JComponent.java:5165)
    at javax.swing.JComponent.paintImmediately(JComponent.java:4976)
    at javax.swing.RepaintManager$3.run(RepaintManager.java:811)
    at javax.swing.RepaintManager$3.run(RepaintManager.java:794)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75)
    at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:794)
    at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:769)
    at javax.swing.RepaintManager.prePaintDirtyRegions(RepaintManager.java:718)
    at javax.swing.RepaintManager.access$1100(RepaintManager.java:62)
    at javax.swing.RepaintManager$ProcessingRunnable.run(RepaintManager.java:1680)
    at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:311)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:744)
    at java.awt.EventQueue.access$400(EventQueue.java:97)
    at java.awt.EventQueue$3.run(EventQueue.java:697)
    at java.awt.EventQueue$3.run(EventQueue.java:691)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:714)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
    at javax.swing.plaf.synth.SynthComboBoxUI.paintCurrentValue(SynthComboBoxUI.java:379)
    at javax.swing.plaf.synth.SynthComboBoxUI.paint(SynthComboBoxUI.java:358)
    at javax.swing.plaf.synth.SynthComboBoxUI.update(SynthComboBoxUI.java:326)
    at javax.swing.JComponent.paintComponent(JComponent.java:777)
    at javax.swing.JComponent.paint(JComponent.java:1053)
    at javax.swing.JComponent.paintChildren(JComponent.java:886)
    at javax.swing.JComponent.paint(JComponent.java:1062)
    at javax.swing.JComponent.paintChildren(JComponent.java:886)
    at javax.swing.JComponent.paint(JComponent.java:1062)
    at javax.swing.JComponent.paintChildren(JComponent.java:886)
    at javax.swing.JComponent.paint(JComponent.java:1062)
    at javax.swing.JComponent.paintChildren(JComponent.java:886)
    at javax.swing.JComponent.paint(JComponent.java:1062)
    at javax.swing.JLayeredPane.paint(JLayeredPane.java:586)
    at javax.swing.JComponent.paintToOffscreen(JComponent.java:5217)
    at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(RepaintManager.java:1532)
    at javax.swing.RepaintManager$PaintManager.paint(RepaintManager.java:1455)
    at javax.swing.RepaintManager.paint(RepaintManager.java:1252)
    at javax.swing.JComponent._paintImmediately(JComponent.java:5165)
    at javax.swing.JComponent.paintImmediately(JComponent.java:4976)
    at javax.swing.RepaintManager$3.run(RepaintManager.java:811)
    at javax.swing.RepaintManager$3.run(RepaintManager.java:794)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75)
    at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:794)
    at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:769)
    at javax.swing.RepaintManager.prePaintDirtyRegions(RepaintManager.java:718)
    at javax.swing.RepaintManager.access$1100(RepaintManager.java:62)
    at javax.swing.RepaintManager$ProcessingRunnable.run(RepaintManager.java:1680)
    at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:311)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:744)
    at java.awt.EventQueue.access$400(EventQueue.java:97)
    at java.awt.EventQueue$3.run(EventQueue.java:697)
    at java.awt.EventQueue$3.run(EventQueue.java:691)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:714)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
    at javax.swing.plaf.synth.SynthComboBoxUI.paintCurrentValue(SynthComboBoxUI.java:379)
    at javax.swing.plaf.synth.SynthComboBoxUI.paint(SynthComboBoxUI.java:358)
    at javax.swing.plaf.synth.SynthComboBoxUI.update(SynthComboBoxUI.java:326)
    at javax.swing.JComponent.paintComponent(JComponent.java:777)
    at javax.swing.JComponent.paint(JComponent.java:1053)
    at javax.swing.JComponent.paintChildren(JComponent.java:886)
    at javax.swing.JComponent.paint(JComponent.java:1062)
    at javax.swing.JComponent.paintChildren(JComponent.java:886)
    at javax.swing.JComponent.paint(JComponent.java:1062)
    at javax.swing.JComponent.paintChildren(JComponent.java:886)
    at javax.swing.JComponent.paint(JComponent.java:1062)
    at javax.swing.JComponent.paintChildren(JComponent.java:886)
    at javax.swing.JComponent.paint(JComponent.java:1062)
    at javax.swing.JLayeredPane.paint(JLayeredPane.java:586)
    at javax.swing.JComponent.paintToOffscreen(JComponent.java:5217)
    at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(RepaintManager.java:1532)
    at javax.swing.RepaintManager$PaintManager.paint(RepaintManager.java:1455)
    at javax.swing.RepaintManager.paint(RepaintManager.java:1252)
    at javax.swing.JComponent._paintImmediately(JComponent.java:5165)
    at javax.swing.JComponent.paintImmediately(JComponent.java:4976)
    at javax.swing.RepaintManager$3.run(RepaintManager.java:811)
    at javax.swing.RepaintManager$3.run(RepaintManager.java:794)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75)
    at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:794)
    at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:769)
    at javax.swing.RepaintManager.prePaintDirtyRegions(RepaintManager.java:718)
    at javax.swing.RepaintManager.access$1100(RepaintManager.java:62)
    at javax.swing.RepaintManager$ProcessingRunnable.run(RepaintManager.java:1680)
    at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:311)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:744)
    at java.awt.EventQueue.access$400(EventQueue.java:97)
    at java.awt.EventQueue$3.run(EventQueue.java:697)
    at java.awt.EventQueue$3.run(EventQueue.java:691)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:714)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
    at javax.swing.plaf.synth.SynthComboBoxUI.paintCurrentValue(SynthComboBoxUI.java:379)
    at javax.swing.plaf.synth.SynthComboBoxUI.paint(SynthComboBoxUI.java:358)
    at javax.swing.plaf.synth.SynthComboBoxUI.update(SynthComboBoxUI.java:326)
    at javax.swing.JComponent.paintComponent(JComponent.java:777)
    at javax.swing.JComponent.paint(JComponent.java:1053)
    at javax.swing.JComponent.paintChildren(JComponent.java:886)
    at javax.swing.JComponent.paint(JComponent.java:1062)
    at javax.swing.JComponent.paintChildren(JComponent.java:886)
    at javax.swing.JComponent.paint(JComponent.java:1062)
    at javax.swing.JComponent.paintChildren(JComponent.java:886)
    at javax.swing.JComponent.paint(JComponent.java:1062)
    at javax.swing.JComponent.paintChildren(JComponent.java:886)
    at javax.swing.JComponent.paint(JComponent.java:1062)
    at javax.swing.JLayeredPane.paint(JLayeredPane.java:586)
    at javax.swing.JComponent.paintToOffscreen(JComponent.java:5217)
    at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(RepaintManager.java:1532)
    at javax.swing.RepaintManager$PaintManager.paint(RepaintManager.java:1455)
    at javax.swing.RepaintManager.paint(RepaintManager.java:1252)
    at javax.swing.JComponent._paintImmediately(JComponent.java:5165)
    at javax.swing.JComponent.paintImmediately(JComponent.java:4976)
    at javax.swing.RepaintManager$3.run(RepaintManager.java:811)
    at javax.swing.RepaintManager$3.run(RepaintManager.java:794)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75)
    at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:794)
    at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:769)
    at javax.swing.RepaintManager.prePaintDirtyRegions(RepaintManager.java:718)
    at javax.swing.RepaintManager.access$1100(RepaintManager.java:62)
    at javax.swing.RepaintManager$ProcessingRunnable.run(RepaintManager.java:1680)
    at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:311)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:744)
    at java.awt.EventQueue.access$400(EventQueue.java:97)
    at java.awt.EventQueue$3.run(EventQueue.java:697)
    at java.awt.EventQueue$3.run(EventQueue.java:691)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:714)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
    at javax.swing.plaf.synth.SynthComboBoxUI.paintCurrentValue(SynthComboBoxUI.java:379)
    at javax.swing.plaf.synth.SynthComboBoxUI.paint(SynthComboBoxUI.java:358)
    at javax.swing.plaf.synth.SynthComboBoxUI.update(SynthComboBoxUI.java:326)
    at javax.swing.JComponent.paintComponent(JComponent.java:777)
    at javax.swing.JComponent.paint(JComponent.java:1053)
    at javax.swing.JComponent.paintChildren(JComponent.java:886)
    at javax.swing.JComponent.paint(JComponent.java:1062)
    at javax.swing.JComponent.paintChildren(JComponent.java:886)
    at javax.swing.JComponent.paint(JComponent.java:1062)
    at javax.swing.JComponent.paintChildren(JComponent.java:886)
    at javax.swing.JComponent.paint(JComponent.java:1062)
    at javax.swing.JComponent.paintChildren(JComponent.java:886)
    at javax.swing.JComponent.paint(JComponent.java:1062)
    at javax.swing.JLayeredPane.paint(JLayeredPane.java:586)
    at javax.swing.JComponent.paintToOffscreen(JComponent.java:5217)
    at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(RepaintManager.java:1532)
    at javax.swing.RepaintManager$PaintManager.paint(RepaintManager.java:1455)
    at javax.swing.RepaintManager.paint(RepaintManager.java:1252)
    at javax.swing.JComponent._paintImmediately(JComponent.java:5165)
    at javax.swing.JComponent.paintImmediately(JComponent.java:4976)
    at javax.swing.RepaintManager$3.run(RepaintManager.java:811)
    at javax.swing.RepaintManager$3.run(RepaintManager.java:794)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75)
    at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:794)
    at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:769)
    at javax.swing.RepaintManager.prePaintDirtyRegions(RepaintManager.java:718)
    at javax.swing.RepaintManager.access$1100(RepaintManager.java:62)
    at javax.swing.RepaintManager$ProcessingRunnable.run(RepaintManager.java:1680)
    at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:311)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:744)
    at java.awt.EventQueue.access$400(EventQueue.java:97)
    at java.awt.EventQueue$3.run(EventQueue.java:697)
    at java.awt.EventQueue$3.run(EventQueue.java:691)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:714)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
    at javax.swing.plaf.synth.SynthComboBoxUI.paintCurrentValue(SynthComboBoxUI.java:379)
    at javax.swing.plaf.synth.SynthComboBoxUI.paint(SynthComboBoxUI.java:358)
    at javax.swing.plaf.synth.SynthComboBoxUI.update(SynthComboBoxUI.java:326)
    at javax.swing.JComponent.paintComponent(JComponent.java:777)
    at javax.swing.JComponent.paint(JComponent.java:1053)
    at javax.swing.JComponent.paintChildren(JComponent.java:886)
    at javax.swing.JComponent.paint(JComponent.java:1062)
    at javax.swing.JComponent.paintChildren(JComponent.java:886)
    at javax.swing.JComponent.paint(JComponent.java:1062)
    at javax.swing.JComponent.paintChildren(JComponent.java:886)
    at javax.swing.JComponent.paint(JComponent.java:1062)
    at javax.swing.JComponent.paintChildren(JComponent.java:886)
    at javax.swing.JComponent.paint(JComponent.java:1062)
    at javax.swing.JLayeredPane.paint(JLayeredPane.java:586)
    at javax.swing.JComponent.paintChildren(JComponent.java:886)
    at javax.swing.JComponent.paint(JComponent.java:1062)
    at javax.swing.JComponent.paintToOffscreen(JComponent.java:5217)
    at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(RepaintManager.java:1532)
    at javax.swing.RepaintManager$PaintManager.paint(RepaintManager.java:1455)
    at javax.swing.RepaintManager.paint(RepaintManager.java:1252)
    at javax.swing.JComponent._paintImmediately(JComponent.java:5165)
    at javax.swing.JComponent.paintImmediately(JComponent.java:4976)
    at javax.swing.RepaintManager$3.run(RepaintManager.java:811)
    at javax.swing.RepaintManager$3.run(RepaintManager.java:794)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75)
    at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:794)
    at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:769)
    at javax.swing.RepaintManager.prePaintDirtyRegions(RepaintManager.java:718)
    at javax.swing.RepaintManager.access$1100(RepaintManager.java:62)
    at javax.swing.RepaintManager$ProcessingRunnable.run(RepaintManager.java:1680)
    at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:311)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:744)
    at java.awt.EventQueue.access$400(EventQueue.java:97)
    at java.awt.EventQueue$3.run(EventQueue.java:697)
    at java.awt.EventQueue$3.run(EventQueue.java:691)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:714)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:109)
    at java.awt.WaitDispatchSupport$2.run(WaitDispatchSupport.java:184)
    at java.awt.WaitDispatchSupport$4.run(WaitDispatchSupport.java:229)
    at java.awt.WaitDispatchSupport$4.run(WaitDispatchSupport.java:227)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.awt.WaitDispatchSupport.enter(WaitDispatchSupport.java:227)
    at java.awt.Dialog.show(Dialog.java:1084)
    at javax.swing.JOptionPane.showOptionDialog(JOptionPane.java:869)
    at javax.swing.JOptionPane.showConfirmDialog(JOptionPane.java:795)
    at javax.swing.JOptionPane.showConfirmDialog(JOptionPane.java:757)
    at javax.swing.JOptionPane.showConfirmDialog(JOptionPane.java:718)
    at Prova.GUI_Overview.windowClosing(GUI_Overview.java:87)
    at java.awt.AWTEventMulticaster.windowClosing(AWTEventMulticaster.java:350)
    at java.awt.AWTEventMulticaster.windowClosing(AWTEventMulticaster.java:349)
    at java.awt.Window.processWindowEvent(Window.java:2058)
    at javax.swing.JFrame.processWindowEvent(JFrame.java:297)
    at java.awt.Window.processEvent(Window.java:2017)
    at java.awt.Component.dispatchEventImpl(Component.java:4883)
    at java.awt.Container.dispatchEventImpl(Container.java:2292)
    at java.awt.Window.dispatchEventImpl(Window.java:2739)
    at java.awt.Component.dispatchEvent(Component.java:4705)
    at de.javasoft.plaf.synthetica.SyntheticaTitlePane.close(SyntheticaTitlePane.java:1256)
    at de.javasoft.plaf.synthetica.SyntheticaTitlePane.access$2(SyntheticaTitlePane.java:1254)
    at de.javasoft.plaf.synthetica.SyntheticaTitlePane$1.actionPerformed(SyntheticaTitlePane.java:184)
    at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022)
    at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2346)
    at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
    at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
    at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
    at java.awt.AWTEventMulticaster.mouseReleased(AWTEventMulticaster.java:289)
    at java.awt.Component.processMouseEvent(Component.java:6527)
    at javax.swing.JComponent.processMouseEvent(JComponent.java:3321)
    at java.awt.Component.processEvent(Component.java:6292)
    at java.awt.Container.processEvent(Container.java:2234)
    at java.awt.Component.dispatchEventImpl(Component.java:4883)
    at java.awt.Container.dispatchEventImpl(Container.java:2292)
    at java.awt.Component.dispatchEvent(Component.java:4705)
    at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4898)
    at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4533)
    at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4462)
    at java.awt.Container.dispatchEventImpl(Container.java:2278)
    at java.awt.Window.dispatchEventImpl(Window.java:2739)
    at java.awt.Component.dispatchEvent(Component.java:4705)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:746)
    at java.awt.EventQueue.access$400(EventQueue.java:97)
    at java.awt.EventQueue$3.run(EventQueue.java:697)
    at java.awt.EventQueue$3.run(EventQueue.java:691)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:86)
    at java.awt.EventQueue$4.run(EventQueue.java:719)
    at java.awt.EventQueue$4.run(EventQueue.java:717)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:716)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)

Answer 1

  UIManager.setLookAndFeel(new SyntheticaStandardLookAndFeel());

您可以尝试使用上述代码，只是检查您使用的jar文件是否存在问题。