GWT Editor bug?

Question

This is my development environment :

ubuntu 12.04 LTS
Eclipse Version: 3.7.2 (Indigo)
Google Plugin for Eclipse 3.7
Google Web Toolkit 2.4.0
GWT Designer Core 2.5.0
GWT Designer GPE 2.5.0
WindowBuilder Core 1.3.0
WindowBuilder CSS Support 1.2.0
WindowBuilder XML Core 1.3.0

I created a gwt/app engine project with the "App Engine Connected Android Project" and made very modifications (just refactoring a few names).

When I click on my "ui.xml" gwt file, I can display it in the Eclipse editor window "XML Source" tab.

But when I click on the "Design" tab, I get the following error :

Internal Error

encountered unexpected internal error.

This could be caused by a bug or by a misconfiguration issue, conflict, partial update, etc.

java.lang.NoClassDefFoundError: net/sf/cglib/proxy/Callback

Stack trace:

java.lang.ClassNotFoundException: net.sf.cglib.proxy.Callback
at org.eclipse.osgi.internal.loader.BundleLoader.findClassInternal(BundleLoader.java:513)
at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:429)
at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:417)
at org.eclipse.osgi.internal.baseadaptor.DefaultClassLoader.loadClass(DefaultClassLoader.java:107)
at java.lang.ClassLoader.loadClass(ClassLoader.java:356)
at org.eclipse.wb.internal.core.xml.model.EditorContext.<init>(EditorContext.java:59)
at com.google.gdt.eclipse.designer.uibinder.parser.UiBinderContext.<init>(UiBinderContext.java:89)
at com.google.gdt.eclipse.designer.uibinder.editor.UiBinderDesignPage.parse(UiBinderDesignPage.java:101)
at org.eclipse.wb.internal.core.xml.editor.XmlDesignPage.internal_refreshGEF(XmlDesignPage.java:451)
at org.eclipse.wb.internal.core.xml.editor.XmlDesignPage.access$2(XmlDesignPage.java:443)
at org.eclipse.wb.internal.core.xml.editor.XmlDesignPage$7$1.run(XmlDesignPage.java:417)
at org.eclipse.swt.widgets.Synchronizer.syncExec(Synchronizer.java:180)
at org.eclipse.ui.internal.UISynchronizer.syncExec(UISynchronizer.java:150)
at org.eclipse.swt.widgets.Display.syncExec(Display.java:4330)
at org.eclipse.wb.internal.core.xml.editor.XmlDesignPage$7.run(XmlDesignPage.java:414)
at org.eclipse.jface.operation.ModalContext.runInCurrentThread(ModalContext.java:464)
at org.eclipse.jface.operation.ModalContext.run(ModalContext.java:372)
at org.eclipse.jface.dialogs.ProgressMonitorDialog.run(ProgressMonitorDialog.java:507)
at org.eclipse.wb.internal.core.xml.editor.XmlDesignPage.internal_refreshGEF_withProgress(XmlDesignPage.java:435)
at org.eclipse.wb.internal.core.xml.editor.XmlDesignPage.internal_refreshGEF(XmlDesignPage.java:388)
at org.eclipse.wb.internal.core.xml.editor.UndoManager.refreshDesignerEditor(UndoManager.java:252)
at org.eclipse.wb.internal.core.xml.editor.XmlDesignPage.updateGEF(XmlDesignPage.java:361)
at org.eclipse.wb.internal.core.xml.editor.XmlDesignPage.refreshGEF(XmlDesignPage.java:354)
at org.eclipse.wb.internal.core.xml.editor.actions.RefreshAction.run(RefreshAction.java:47)
at org.eclipse.wb.internal.core.xml.editor.actions.DesignPageAction.run(DesignPageAction.java:35)
at org.eclipse.wb.internal.core.xml.editor.XmlExceptionComposite.doRefresh(XmlExceptionComposite.java:65)
at org.eclipse.wb.internal.core.editor.errors.ExceptionComposite$3.widgetSelected(ExceptionComposite.java:129)
at org.eclipse.swt.widgets.TypedListener.handleEvent(TypedListener.java:240)
at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1258)
at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:3588)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3209)
at org.eclipse.ui.internal.Workbench.runEventLoop(Workbench.java:2701)
at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:2665)
at org.eclipse.ui.internal.Workbench.access$4(Workbench.java:2499)
at org.eclipse.ui.internal.Workbench$7.run(Workbench.java:679)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:668)
at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149)
at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:123)
at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:110)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:79)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:344)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:179)
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:601)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:622)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:577)
at org.eclipse.equinox.launcher.Main.run(Main.java:1410)
at org.eclipse.equinox.launcher.Main.main(Main.java:1386)

Full context stack trace:

java.lang.NoClassDefFoundError: net/sf/cglib/proxy/Callback
at org.eclipse.wb.internal.core.xml.model.EditorContext.<init>(EditorContext.java:59)
at com.google.gdt.eclipse.designer.uibinder.parser.UiBinderContext.<init>(UiBinderContext.java:89)
at com.google.gdt.eclipse.designer.uibinder.editor.UiBinderDesignPage.parse(UiBinderDesignPage.java:101)
at org.eclipse.wb.internal.core.xml.editor.XmlDesignPage.internal_refreshGEF(XmlDesignPage.java:451)
at org.eclipse.wb.internal.core.xml.editor.XmlDesignPage.access$2(XmlDesignPage.java:443)
at org.eclipse.wb.internal.core.xml.editor.XmlDesignPage$7$1.run(XmlDesignPage.java:417)
at org.eclipse.swt.widgets.Synchronizer.syncExec(Synchronizer.java:180)
at org.eclipse.ui.internal.UISynchronizer.syncExec(UISynchronizer.java:150)
at org.eclipse.swt.widgets.Display.syncExec(Display.java:4330)
at org.eclipse.wb.internal.core.xml.editor.XmlDesignPage$7.run(XmlDesignPage.java:414)
at org.eclipse.jface.operation.ModalContext.runInCurrentThread(ModalContext.java:464)
at org.eclipse.jface.operation.ModalContext.run(ModalContext.java:372)
at org.eclipse.jface.dialogs.ProgressMonitorDialog.run(ProgressMonitorDialog.java:507)
at org.eclipse.wb.internal.core.xml.editor.XmlDesignPage.internal_refreshGEF_withProgress(XmlDesignPage.java:435)
at org.eclipse.wb.internal.core.xml.editor.XmlDesignPage.internal_refreshGEF(XmlDesignPage.java:388)
at org.eclipse.wb.internal.core.xml.editor.UndoManager.refreshDesignerEditor(UndoManager.java:252)
at org.eclipse.wb.internal.core.xml.editor.XmlDesignPage.updateGEF(XmlDesignPage.java:361)
at org.eclipse.wb.internal.core.xml.editor.XmlDesignPage.refreshGEF(XmlDesignPage.java:354)
at org.eclipse.wb.internal.core.xml.editor.actions.RefreshAction.run(RefreshAction.java:47)
at org.eclipse.wb.internal.core.xml.editor.actions.DesignPageAction.run(DesignPageAction.java:35)
at org.eclipse.wb.internal.core.xml.editor.XmlExceptionComposite.doRefresh(XmlExceptionComposite.java:65)
at org.eclipse.wb.internal.core.editor.errors.ExceptionComposite$3.widgetSelected(ExceptionComposite.java:129)
at org.eclipse.swt.widgets.TypedListener.handleEvent(TypedListener.java:240)
at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1258)
at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:3588)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3209)
at org.eclipse.ui.internal.Workbench.runEventLoop(Workbench.java:2701)
at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:2665)
at org.eclipse.ui.internal.Workbench.access$4(Workbench.java:2499)
at org.eclipse.ui.internal.Workbench$7.run(Workbench.java:679)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:668)
at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149)
at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:123)
at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:110)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:79)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:344)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:179)
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:601)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:622)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:577)
at org.eclipse.equinox.launcher.Main.run(Main.java:1410)
at org.eclipse.equinox.launcher.Main.main(Main.java:1386)
Caused by: java.lang.ClassNotFoundException: net.sf.cglib.proxy.Callback
at org.eclipse.osgi.internal.loader.BundleLoader.findClassInternal(BundleLoader.java:513)
at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:429)
at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:417)
at org.eclipse.osgi.internal.baseadaptor.DefaultClassLoader.loadClass(DefaultClassLoader.java:107)
at java.lang.ClassLoader.loadClass(ClassLoader.java:356)
... 48 more

Ümit Ümit · Accepted Answer · 2012-06-23T13:32:23

The important line in your stacktrace is:

java.lang.ClassNotFoundException: net.sf.cglib.proxy.Callback

Apparently somewhere in your GWT code you reference the Callbackclass from the net.sf.cglib.proxypackage. If you reference any package or class in your GWT code you must have the source code in order for the GWT compiler to be able to translate it to javascript.

However this net.sf.cglib.proxypackage belongs to the cglib.jar which is a Bytecode manipulation library. This library is not supported in GWT.
Check your source code for references to net.sf.cglib.proxy.Callback.
I assume you imported the wrong package.

GWT Editor bug?

1 Answers