我想将我的Eclipse RCP应用程序从3.x移植到4.x。
现在，我已经建立了我的项目，它的构建没有错误。
执行该应用程序后，在加载PerspectiveSwitcherToolbar时会抛出IllegalArgumentException。
PerspectiveSwitcherToolbar扩展了ContributionItem。最初它扩展了ControlContibution，但由于需要在多个角度共享它，因此我们对其进行了更改。 Here是说明如何完成此操作的教程。
!MESSAGE Loaded class is of incorrect type: expected(org.eclipse.ui.menus.WorkbenchWindowControlContribution) got (PerspectiveSwitcherToolbar)
!STACK 0
java.lang.IllegalArgumentException: Loaded class is of incorrect type: expected(org.eclipse.ui.menus.WorkbenchWindowControlContribution) got (PerspectiveSwitcherToolbar)
at org.eclipse.ui.internal.util.Util.safeLoadExecutableExtension(Util.java:799)
at org.eclipse.ui.internal.menus.CompatibilityWorkbenchWindowControlContribution.construct(CompatibilityWorkbenchWindowControlContribution.java:54)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.eclipse.e4.core.internal.di.MethodRequestor.execute(MethodRequestor.java:55)
at org.eclipse.e4.core.internal.di.InjectorImpl.processAnnotated(InjectorImpl.java:1005)
at org.eclipse.e4.core.internal.di.InjectorImpl.internalInject(InjectorImpl.java:137)
at org.eclipse.e4.core.internal.di.InjectorImpl.internalMake(InjectorImpl.java:412)
at org.eclipse.e4.core.internal.di.InjectorImpl.make(InjectorImpl.java:345)
at org.eclipse.e4.core.contexts.ContextInjectionFactory.make(ContextInjectionFactory.java:214)
at org.eclipse.e4.ui.internal.workbench.ReflectionContributionFactory.createFromBundle(ReflectionContributionFactory.java:108)
at org.eclipse.e4.ui.internal.workbench.ReflectionContributionFactory.doCreate(ReflectionContributionFactory.java:74)
at org.eclipse.e4.ui.internal.workbench.ReflectionContributionFactory.create(ReflectionContributionFactory.java:51)
at org.eclipse.e4.ui.workbench.renderers.swt.ToolControlContribution.createControl(ToolControlContribution.java:53)
at org.eclipse.jface.action.ControlContribution.fill(ControlContribution.java:101)
at org.eclipse.jface.action.ToolBarManager.update(ToolBarManager.java:343)
at org.eclipse.e4.ui.workbench.renderers.swt.ToolBarManagerRenderer.subscribeTopicUpdateToBeRendered(ToolBarManagerRenderer.java:213)
at sun.reflect.GeneratedMethodAccessor27.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.eclipse.e4.core.internal.di.MethodRequestor.execute(MethodRequestor.java:55)
at org.eclipse.e4.ui.internal.di.UIEventObjectSupplier$UIEventHandler$1.run(UIEventObjectSupplier.java:64)
at org.eclipse.swt.widgets.Synchronizer.syncExec(Synchronizer.java:233)
at org.eclipse.ui.internal.UISynchronizer.syncExec(UISynchronizer.java:144)
at org.eclipse.swt.widgets.Display.syncExec(Display.java:4567)
at org.eclipse.e4.ui.internal.workbench.swt.E4Application$1.syncExec(E4Application.java:212)
at org.eclipse.e4.ui.internal.di.UIEventObjectSupplier$UIEventHandler.handleEvent(UIEventObjectSupplier.java:61)
at org.eclipse.equinox.internal.event.EventHandlerWrapper.handleEvent(EventHandlerWrapper.java:201)
at org.eclipse.equinox.internal.event.EventHandlerTracker.dispatchEvent(EventHandlerTracker.java:196)
at org.eclipse.equinox.internal.event.EventHandlerTracker.dispatchEvent(EventHandlerTracker.java:1)
at org.eclipse.osgi.framework.eventmgr.EventManager.dispatchEvent(EventManager.java:230)
at org.eclipse.osgi.framework.eventmgr.ListenerQueue.dispatchEventSynchronous(ListenerQueue.java:148)
at org.eclipse.equinox.internal.event.EventAdminImpl.dispatchEvent(EventAdminImpl.java:135)
at org.eclipse.equinox.internal.event.EventAdminImpl.sendEvent(EventAdminImpl.java:78)
at org.eclipse.equinox.internal.event.EventComponent.sendEvent(EventComponent.java:39)
at org.eclipse.e4.ui.services.internal.events.EventBroker.send(EventBroker.java:52)
at org.eclipse.e4.ui.internal.workbench.UIEventPublisher.notifyChanged(UIEventPublisher.java:60)
at org.eclipse.emf.common.notify.impl.BasicNotifierImpl.eNotify(BasicNotifierImpl.java:374)
at org.eclipse.e4.ui.model.application.ui.impl.UIElementImpl.setVisible(UIElementImpl.java:346)
at org.eclipse.e4.ui.workbench.renderers.swt.ToolBarContributionRecord.updateVisibility(ToolBarContributionRecord.java:71)
at org.eclipse.e4.ui.workbench.renderers.swt.ToolBarManagerRenderer$2.changed(ToolBarManagerRenderer.java:479)
at org.eclipse.e4.core.internal.contexts.TrackableComputationExt.update(TrackableComputationExt.java:114)
at org.eclipse.e4.core.internal.contexts.EclipseContext.runAndTrack(EclipseContext.java:344)
at org.eclipse.e4.ui.workbench.renderers.swt.ToolBarManagerRenderer.processAddition(ToolBarManagerRenderer.java:471)
at org.eclipse.e4.ui.workbench.renderers.swt.ToolBarManagerRenderer.generateContributions(ToolBarManagerRenderer.java:447)
at org.eclipse.e4.ui.workbench.renderers.swt.ToolBarManagerRenderer.processContribution(ToolBarManagerRenderer.java:416)
at org.eclipse.e4.ui.workbench.renderers.swt.ToolBarManagerRenderer.createWidget(ToolBarManagerRenderer.java:376)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.createWidget(PartRenderingEngine.java:1012)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.safeCreateGui(PartRenderingEngine.java:672)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.safeCreateGui(PartRenderingEngine.java:778)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.access$0(PartRenderingEngine.java:749)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$2.run(PartRenderingEngine.java:743)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.createGui(PartRenderingEngine.java:727)
at org.eclipse.e4.ui.workbench.renderers.swt.SWTPartRenderer.processContents(SWTPartRenderer.java:70)
at org.eclipse.e4.ui.workbench.renderers.swt.TrimBarRenderer.processContents(TrimBarRenderer.java:127)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.safeCreateGui(PartRenderingEngine.java:686)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$1.run(PartRenderingEngine.java:557)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.createGui(PartRenderingEngine.java:541)
at org.eclipse.e4.ui.workbench.renderers.swt.WBWRenderer.processContents(WBWRenderer.java:722)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.safeCreateGui(PartRenderingEngine.java:686)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.safeCreateGui(PartRenderingEngine.java:778)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.access$0(PartRenderingEngine.java:749)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$2.run(PartRenderingEngine.java:743)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.createGui(PartRenderingEngine.java:727)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$5.run(PartRenderingEngine.java:1096)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:336)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.run(PartRenderingEngine.java:1059)
at org.eclipse.e4.ui.internal.workbench.E4Workbench.createAndRunUI(E4Workbench.java:153)
at org.eclipse.ui.internal.Workbench.lambda$3(Workbench.java:667)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:336)
at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:597)
at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:148)
at com.Application.start(Application.java:37)
at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:134)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:104)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:388)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:243)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:656)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:592)
at org.eclipse.equinox.launcher.Main.run(Main.java:1498)
at org.eclipse.equinox.launcher.Main.main(Main.java:1471)
指定的问题是PerspectiveSwitcherToolbar应该扩展WorkbenchWindowControlContribution。目前，它扩展了ContributionItem，在RCP 3中可以正常工作。
我尝试更改PerspectiveSwitcherToolbar以使其扩展WorkbenchWindowControlContribution，但是一开始并没有调用createControl方法。
对此有哪些可能的解决方案？