新发现！在File菜单下单击Export Graphic...， 在命令框中出现如下错误信息：

Exception in thread "AWT-EventQueue-0" java.lang.ExceptionInInitializerError

at org.freehep.graphicsio.gif.GIFImageWriteParam.(GIFImageWriteParam.java:28)

at org.freehep.graphicsio.gif.GIFImageWriter.getDefaultWriteParam(GIFImageWriter.java:73)

at org.freehep.graphicsio.exportchooser.ImageExportFileType.(ImageExportFileType.java:71)

at org.freehep.graphicsio.gif.GIFExportFileType.(GIFExportFileType.java:42)

at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)

at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)

at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)

at java.lang.reflect.Constructor.newInstance(Constructor.java:532)

at java.lang.Class.newInstance0(Class.java:374)

at java.lang.Class.newInstance(Class.java:327)

at org.freehep.util.Service.providers(Service.java:71)

at org.freehep.util.export.ExportFileTypeRegistry.addApplicationClasspathExportFileTypes(ExportFileTypeRegistry.java:118)

at org.freehep.util.export.ExportFileTypeRegistry.getDefaultInstance(ExportFileTypeRegistry.java:50)

at org.freehep.util.export.ExportFileType.getExportFileTypes(ExportFileType.java:181)

at org.freehep.util.export.ExportFileType.getExportFileTypes(ExportFileType.java:173)

at org.freehep.util.export.ExportDialog.addAllExportFileTypes(ExportDialog.java:64)

at org.freehep.util.export.ExportDialog.(ExportDialog.java:130)

at org.freehep.util.export.ExportDialog.(ExportDialog.java:90)

at org.freehep.util.export.ExportDialog.(ExportDialog.java:82)

at figtree.application.FigTreeFrame.doExportGraphic(Unknown Source)

at figtree.application.FigTreeFrame$22.actionPerformed(Unknown Source)

at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2012)

at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2335)

at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:404)

at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)

at javax.swing.AbstractButton.doClick(AbstractButton.java:374)

at javax.swing.plaf.basic.BasicMenuItemUI.doClick(BasicMenuItemUI.java:829)

at javax.swing.plaf.basic.BasicMenuItemUI$Handler.mouseReleased(BasicMenuItemUI.java:873)

at java.awt.Component.processMouseEvent(Component.java:6288)

at javax.swing.JComponent.processMouseEvent(JComponent.java:3267)

at java.awt.Component.processEvent(Component.java:6053)

at java.awt.Container.processEvent(Container.java:2045)

at java.awt.Component.dispatchEventImpl(Component.java:4649)

at java.awt.Container.dispatchEventImpl(Container.java:2103)

at java.awt.Component.dispatchEvent(Component.java:4475)

at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4633)

at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4297)

at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4227)

at java.awt.Container.dispatchEventImpl(Container.java:2089)

at java.awt.Window.dispatchEventImpl(Window.java:2587)

at java.awt.Component.dispatchEvent(Component.java:4475)

at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:675)

at java.awt.EventQueue.access$300(EventQueue.java:96)

at java.awt.EventQueue$2.run(EventQueue.java:634)

at java.awt.EventQueue$2.run(EventQueue.java:632)

at java.security.AccessController.doPrivileged(Native Method)

at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:105)

at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:116)

at java.awt.EventQueue$3.run(EventQueue.java:648)

at java.awt.EventQueue$3.run(EventQueue.java:646)

at java.security.AccessController.doPrivileged(Native Method)

at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:105)

at java.awt.EventQueue.dispatchEvent(EventQueue.java:645)

at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:275)

at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:200)

at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:190)

at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:185)

at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:177)

at java.awt.EventDispatchThread.run(EventDispatchThread.java:138)

Caused by: java.lang.NullPointerException

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

at java.lang.reflect.Method.invoke(Method.java:616)

at org.freehep.graphics2d.PixelGraphics2D.(PixelGraphics2D.java:101)

... 59 more，