由于Eclipse版本不符造成的异常
前几天把GEF版本从3.0.1升级到了3.1M6，发现以前运行正常的GEF程序现在总出现下面这个异常，例如在我移动一个节点时，或者创建一个新节点时。
!ENTRY org.eclipse.ui 4 0 2005-04-19 23:12:55.974!MESSAGE tried to access method org.eclipse.ui.views.properties.PropertySheetEntry.refreshFromRoot()V from class org.eclipse.gef.ui.properties.UndoablePropertySheetEntry!STACK 0java.lang.IllegalAccessError: tried to access method org.eclipse.ui.views.properties.PropertySheetEntry.refreshFromRoot()V from class org.eclipse.gef.ui.properties.UndoablePropertySheetEntry at org.eclipse.gef.ui.properties.UndoablePropertySheetEntry.access$0(UndoablePropertySheetEntry.java:1) at org.eclipse.gef.ui.properties.UndoablePropertySheetEntry$1.commandStackChanged(UndoablePropertySheetEntry.java:103) at org.eclipse.gef.commands.CommandStack.notifyListeners(CommandStack.java:253) at org.eclipse.gef.commands.CommandStack.execute(CommandStack.java:141) at org.eclipse.gef.tools.AbstractTool.executeCommand(AbstractTool.java:374) at org.eclipse.gef.tools.AbstractTool.executeCurrentCommand(AbstractTool.java:386) at org.eclipse.gef.tools.DragEditPartsTracker.performDrag(DragEditPartsTracker.java:450) at org.eclipse.gef.tools.DragEditPartsTracker.handleButtonUp(DragEditPartsTracker.java:320) at org.eclipse.gef.tools.AbstractTool.mouseUp(AbstractTool.java:1035) at org.eclipse.gef.tools.SelectionTool.mouseUp(SelectionTool.java:545) at org.eclipse.gef.EditDomain.mouseUp(EditDomain.java:259) at org.eclipse.gef.ui.parts.DomainEventDispatcher.dispatchMouseReleased(DomainEventDispatcher.java:374) at org.eclipse.draw2d.LightweightSystem$EventHandler.mouseUp(LightweightSystem.java:548) at org.eclipse.swt.widgets.TypedListener.handleEvent(TypedListener.java:136) at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:82) at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:842) at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:2908) at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:2541) at org.eclipse.ui.internal.Workbench.runEventLoop(Workbench.java:1612) at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:1578) at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:293) at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:144) at org.eclipse.ui.internal.ide.IDEApplication.run(IDEApplication.java:102) at org.eclipse.core.internal.runtime.PlatformActivator$1.run(PlatformActivator.java:228) at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:333) at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:150) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Unknown Source) at org.eclipse.core.launcher.Main.invokeFramework(Main.java:268) at org.eclipse.core.launcher.Main.basicRun(Main.java:260) at org.eclipse.core.launcher.Main.run(Main.java:887) at org.eclipse.core.launcher.Main.main(Main.java:871)调试了很久也没找到原因，最后在GEF新闻组里得到了答案，原来GEF3.1M6要求Eclipse的版本在3.1M6或以上，而我正在使用的是Eclipse 3.1M5a，换到3.1M6一试果然OK。
如果你遇到类似的奇怪异常，不妨也先检查一下Eclipse和插件的版本。
