在Jcreator中使用Swing的问题，大家帮帮忙。

import javax.swing.JFrame;
import java.awt.*;
public class GbFrame {
public static void main(String args[]) throws Exception
{
JFrame jf=new JFrame();
jf.setTitle("GoBang");
jf.setVisible(true);
jf.setSize(350,350);
jf.setResizable(false);
jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
int weidth=Toolkit.getDefaultToolkit().getScreenSize().width;
int height=Toolkit.getDefaultToolkit().getScreenSize().height;
jf.setLocation((weidth-200)/2,(height-100)/2);
}
}
编译通过，但是执行不了，高手指点下，感激不尽！
出现的问题提示如下：
Exception in thread "main" java.lang.ExceptionInInitializerError
at javax.swing.JPanel.updateUI(JPanel.java:109)
at javax.swing.JPanel.<init>(JPanel.java:69)
at javax.swing.JPanel.<init>(JPanel.java:92)
at javax.swing.JPanel.<init>(JPanel.java:100)
at javax.swing.JRootPane.createGlassPane(JRootPane.java:527)
at javax.swing.JRootPane.<init>(JRootPane.java:347)
at javax.swing.JFrame.createRootPane(JFrame.java:260)
at javax.swing.JFrame.frameInit(JFrame.java:241)
at javax.swing.JFrame.<init>(JFrame.java:164)
at GbFrame.main(GbFrame.java:14)
Caused by: java.lang.IllegalArgumentException: 90 incompatible with Text-specific LCD contrast key
at java.awt.RenderingHints.put(RenderingHints.java:1057)
at sun.awt.windows.WDesktopProperties.getDesktopAAHints(WDesktopProperties.java:338)
at sun.awt.windows.WToolkit.getDesktopAAHints(WToolkit.java:960)
at sun.awt.SunToolkit.getDesktopFontHints(SunToolkit.java:1833)
at sun.awt.windows.WDesktopProperties.setDesktopAAHints(WDesktopProperties.java:281)
at sun.awt.windows.WToolkit.initializeDesktopProperties(WToolkit.java:948)
at java.awt.Toolkit.getDesktopProperty(Toolkit.java:1734)
at javax.swing.UIManager.<clinit>(UIManager.java:384)
... 10 more

Process completed.