今天我将我的Netbeans 6.8更新为新的Netbeans 7.4，将JDK 1.7.0更新为1.7.0_45当我在新Netbeans版本上打开我以前的项目时，sysnthetica look and feel不工作：（其他一切都很好：）
try {
UIManager.setLookAndFeel(new SyntheticaBlackStarLookAndFeel());
new frm_login().setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
这就是错误：
Exception in thread "main" java.lang.NoClassDefFoundError: sun/swing/plaf/synth/SynthUI
at de.javasoft.plaf.synthetica.SyntheticaDefaultLookup.getDefault(SyntheticaDefaultLookup.java:84)
at sun.swing.DefaultLookup.get(DefaultLookup.java:125)
at javax.swing.plaf.basic.BasicButtonListener.getInputMap(BasicButtonListener.java:119)
at javax.swing.plaf.basic.BasicButtonListener.installKeyboardActions(BasicButtonListener.java:95)
at javax.swing.plaf.basic.BasicButtonUI.installKeyboardActions(BasicButtonUI.java:138)
at javax.swing.plaf.basic.BasicButtonUI.installUI(BasicButtonUI.java:90)
at javax.swing.JComponent.setUI(JComponent.java:664)
at javax.swing.AbstractButton.setUI(AbstractButton.java:1807)
at javax.swing.JButton.updateUI(JButton.java:146)
at javax.swing.AbstractButton.init(AbstractButton.java:2172)
at javax.swing.JButton.<init>(JButton.java:136)
at javax.swing.JButton.<init>(JButton.java:90)
at de.javasoft.plaf.synthetica.SyntheticaLookAndFeel.installCompatibilityDefaults(SyntheticaLookAndFeel.java:553)
at de.javasoft.plaf.synthetica.SyntheticaLookAndFeel.access$4(SyntheticaLookAndFeel.java:405)
at de.javasoft.plaf.synthetica.SyntheticaLookAndFeel$2.propertyChange(SyntheticaLookAndFeel.java:313)
at java.beans.PropertyChangeSupport.fire(PropertyChangeSupport.java:335)
at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:327)
at javax.swing.event.SwingPropertyChangeSupport.firePropertyChange(SwingPropertyChangeSupport.java:92)
at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:263)
at javax.swing.UIManager.setLookAndFeel(UIManager.java:545)
at javaapplication1.JavaApplication1.main(JavaApplication1.java:27)
Caused by: java.lang.ClassNotFoundException: sun.swing.plaf.synth.SynthUI
at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
... 21 more
Java Result: 1
发生这种事的原因是什么？我该如何解决此问题？
提前感谢！
很可能您使用的Synthetica版本不支持JDK1.7。下载最新的Synthetica，您应该可以运行
Daniel B 的回答