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Build Identifier: 3.6.0.I20100603-1100 If you stop and uninstall a plug-in that contains a view or editor that was once opened (closed before stop and uninstall was called) something inside the workbench is still holding a reference to the view class. This reference should be replaced by a WeakReference to let the GarbageCollector remove the ClassLoader and the Class if the bundle was uninstalled. I have found one reference inside the org.eclipse.core.internal.expressions.TypeExtension/ org.eclipse.core.internal.expressions.TypeExtensionManager where the class of the receiver is used as a key for the fTypeExtensionMap. But there is still other references which prevent the GarbageCollector from removing uninstalled plug-ins. Reproducible: Always Steps to Reproduce: 1. Create a plug-in (test.holder) with a holder class that holds an array of WeakReferences<Class<?>> 2. Create a thread that checks that array of WeakReferences<Class<?>> to see if the GarbageCollector has already removed the Class inside the WeakReference. 3. create a plug-in (test.view) with a simple view 4. inside the createPartControl() method of the view add the class of the view to the previously create array of WeakReferences 5. open the view via the menu 6. close the view 7. stop the plug-in (test.view) with the osgi console 8. uninstall the plug-in (test.view) with the osgi console 9. request some GarbageCollection (4-5 times) with the osgi console 10. check the array of WeakReferences<Class<?>> inside the test-holder plug-in and you will see that this class will never be removed If you replace the text.view – plug-in with a small osgi bundle that registers a class from its bundle on activation and run the stop and uninstall steps again you will see that this class will be gone after some gc-calls.
If you like I can create a small test scenario and add it to this bug.
(In reply to comment #1) > If you like I can create a small test scenario and add it to this bug. Such contributions are always welcome.
Created attachment 179397 [details] plug-ins for reproduce this bug This Zip contains 4 projects: - test.holder: plug-in holding the WeakReference and a small OSGi Commandline extension for printing some memory information - test.simple.osgi: simple plug-in using only osgi (this works correct) - test.simple.view: simple view (this is not working correct) - test.run.configs: contains two launch configurations + Eclipse View Test: Launch config for not working example + OSGi Test: Launch config for working example
The test.holder plug-in holds WeakReference to classes you specify and a Thread inside this plug-in will remove does WeakReferences if the class is unloaded by the GarbageCollector. I've also added a OSGi CommandProvider so you can display all specified class references inside the test.holder and if it's required fill the memory with some content to try to force the GarbageCollector to run. ---Command's for ClassReferenceHolder--- print - prints the content of the ClassReferenceHolder array fillMemory <memory-in-byte> - allocate some memory for trying to start the gc earlier freeMemory - free the memory allocated with fillMemory <memory-in-byte> printMemory - print the memory usage of the JVM
I was able to reproduce the issue. I see that following objects of following classes are keeping the reference to SimpleTestView object: - org.eclipse.core.runtime.ListenerList - org.Eclipse.ui.ViewPart$1 - org.eclipse.core.internal.registry.ConfigurationElementHandle - org.eclipse.ui.internal.ViewSite By the way. Rene, are you using OSGI console in your product? Are you uninstalling the plugins in runtime? Or you just have noticed such issue and decided to fill the defect?
Created attachment 230935 [details] path to gc roots.png Sorry for typo in my previous comment. I provided there the list of the objects for which SimpleTestView is still keeping references. Attaching path to GC root. It seems that this reference is kept by CompatibilityView.
I performed following test today: 1. Opened view => The number of org.eclipse.ui.internal.e4.compatibility.CompatibilityPart objects increased by 1 2. Closed view and ran gc() => the number remained the same 3. Opened view => The number of org.eclipse.ui.internal.e4.compatibility.CompatibilityPart objects increased by 1 comparing to the number from step 2 4. Closed view and ran gc() => the number decreased by 1 comparing to the number at the end of step 3 5. Opened view => The number of org.eclipse.ui.internal.e4.compatibility.CompatibilityPart objects increased by 1 comparing to number from step 4 6. Closed view and ran gc() => the number decreased by 1 comparing to the number at the end of step 5 This indicates that CompatibilityPart object is not released first time only.
I have further investigated it a bit. 1. I noticed that first time when I close view, there is no instance of the object released. 2. When closing next time, it is gc released the instance created in the previous cycle. 3. The previous instance of the object is ready to be disposed before test.simple.view.SimpleTestView.dispose() is reached. It can be GCed even before org.eclipse.swt.custom.CTabFolder$1.handleEvent(org.eclipse.swt.widgets.Event) line: 283 is executed. Here is full stack trace from SimpleTestView.dispose() method: test.simple.view.SimpleTestView.dispose() line: 36 org.eclipse.ui.internal.e4.compatibility.CompatibilityView(org.eclipse.ui.internal.e4.compatibility.CompatibilityPart).invalidate() line: 226 org.eclipse.ui.internal.e4.compatibility.CompatibilityView(org.eclipse.ui.internal.e4.compatibility.CompatibilityPart).destroy() line: 392 sun.reflect.NativeMethodAccessorImpl.invoke0(java.lang.reflect.Method, java.lang.Object, java.lang.Object[]) line: not available [native method] sun.reflect.NativeMethodAccessorImpl.invoke(java.lang.Object, java.lang.Object[]) line: 60 sun.reflect.DelegatingMethodAccessorImpl.invoke(java.lang.Object, java.lang.Object[]) line: 37 java.lang.reflect.Method.invoke(java.lang.Object, java.lang.Object...) line: 611 org.eclipse.e4.core.internal.di.MethodRequestor.execute() line: 56 org.eclipse.e4.core.internal.di.InjectorImpl.processAnnotated(java.lang.Class<? extends java.lang.annotation.Annotation>, java.lang.Object, java.lang.Class<?>, org.eclipse.e4.core.di.suppliers.PrimaryObjectSupplier, org.eclipse.e4.core.di.suppliers.PrimaryObjectSupplier, java.util.ArrayList<java.lang.Class<?>>) line: 877 org.eclipse.e4.core.internal.di.InjectorImpl.processAnnotated(java.lang.Class<? extends java.lang.annotation.Annotation>, java.lang.Object, java.lang.Class<?>, org.eclipse.e4.core.di.suppliers.PrimaryObjectSupplier, org.eclipse.e4.core.di.suppliers.PrimaryObjectSupplier, java.util.ArrayList<java.lang.Class<?>>) line: 857 org.eclipse.e4.core.internal.di.InjectorImpl.uninject(java.lang.Object, org.eclipse.e4.core.di.suppliers.PrimaryObjectSupplier) line: 179 org.eclipse.e4.core.internal.di.FieldRequestor(org.eclipse.e4.core.internal.di.Requestor).uninject(java.lang.Object, org.eclipse.e4.core.di.suppliers.PrimaryObjectSupplier) line: 142 org.eclipse.e4.core.internal.contexts.ContextObjectSupplier$ContextInjectionListener.update(org.eclipse.e4.core.contexts.IEclipseContext, int, java.lang.Object[]) line: 82 org.eclipse.e4.core.internal.contexts.TrackableComputationExt.update(org.eclipse.e4.core.internal.contexts.ContextChangeEvent) line: 107 org.eclipse.e4.core.internal.contexts.EclipseContext.removeListenersTo(java.lang.Object) line: 456 org.eclipse.e4.core.contexts.ContextInjectionFactory.uninject(java.lang.Object, org.eclipse.e4.core.contexts.IEclipseContext) line: 144 org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.safeRemoveGui(org.eclipse.e4.ui.model.application.ui.MUIElement) line: 908 org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.access$3(org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine, org.eclipse.e4.ui.model.application.ui.MUIElement) line: 828 org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$8.run() line: 823 org.eclipse.core.runtime.SafeRunner.run(org.eclipse.core.runtime.ISafeRunnable) line: 42 org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.removeGui(org.eclipse.e4.ui.model.application.ui.MUIElement) line: 808 org.eclipse.e4.ui.workbench.renderers.swt.ElementReferenceRenderer.disposeWidget(org.eclipse.e4.ui.model.application.ui.MUIElement) line: 109 org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.safeRemoveGui(org.eclipse.e4.ui.model.application.ui.MUIElement) line: 899 org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.access$3(org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine, org.eclipse.e4.ui.model.application.ui.MUIElement) line: 828 org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$8.run() line: 823 org.eclipse.core.runtime.SafeRunner.run(org.eclipse.core.runtime.ISafeRunnable) line: 42 org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.removeGui(org.eclipse.e4.ui.model.application.ui.MUIElement) line: 808 org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$1.handleEvent(org.osgi.service.event.Event) line: 153 org.eclipse.e4.ui.services.internal.events.UIEventHandler$1.run() line: 41 org.eclipse.ui.internal.UISynchronizer(org.eclipse.swt.widgets.Synchronizer).syncExec(java.lang.Runnable) line: 180 org.eclipse.ui.internal.UISynchronizer.syncExec(java.lang.Runnable) line: 150 org.eclipse.swt.widgets.Display.syncExec(java.lang.Runnable) line: 4688 org.eclipse.e4.ui.internal.workbench.swt.E4Application$1.syncExec(java.lang.Runnable) line: 205 org.eclipse.e4.ui.services.internal.events.UIEventHandler.handleEvent(org.osgi.service.event.Event) line: 38 org.eclipse.equinox.internal.event.EventHandlerWrapper.handleEvent(org.osgi.service.event.Event, java.security.Permission) line: 197 org.eclipse.equinox.internal.event.EventHandlerTracker.dispatchEvent(org.eclipse.equinox.internal.event.EventHandlerWrapper, java.security.Permission, int, org.osgi.service.event.Event) line: 197 org.eclipse.equinox.internal.event.EventHandlerTracker.dispatchEvent(java.lang.Object, java.lang.Object, int, java.lang.Object) line: 1 org.eclipse.osgi.framework.eventmgr.EventManager.dispatchEvent(java.util.Set<java.util.Map.Entry<K,V>>, org.eclipse.osgi.framework.eventmgr.EventDispatcher<K,V,E>, int, E) line: 230 org.eclipse.osgi.framework.eventmgr.ListenerQueue<K,V,E>.dispatchEventSynchronous(int, E) line: 148 org.eclipse.equinox.internal.event.EventAdminImpl.dispatchEvent(org.osgi.service.event.Event, boolean) line: 135 org.eclipse.equinox.internal.event.EventAdminImpl.sendEvent(org.osgi.service.event.Event) line: 78 org.eclipse.equinox.internal.event.EventComponent.sendEvent(org.osgi.service.event.Event) line: 39 org.eclipse.e4.ui.services.internal.events.EventBroker.send(java.lang.String, java.lang.Object) line: 80 org.eclipse.e4.ui.internal.workbench.UIEventPublisher.notifyChanged(org.eclipse.emf.common.notify.Notification) line: 58 org.eclipse.e4.ui.model.application.ui.advanced.impl.PlaceholderImpl(org.eclipse.emf.common.notify.impl.BasicNotifierImpl).eNotify(org.eclipse.emf.common.notify.Notification) line: 374 org.eclipse.e4.ui.model.application.ui.advanced.impl.PlaceholderImpl(org.eclipse.e4.ui.model.application.ui.impl.UIElementImpl).setToBeRendered(boolean) line: 290 org.eclipse.e4.ui.internal.workbench.PartServiceImpl.hidePart(org.eclipse.e4.ui.model.application.ui.basic.MPart, boolean) line: 1169 org.eclipse.e4.ui.internal.workbench.PartServiceImpl.hidePart(org.eclipse.e4.ui.model.application.ui.basic.MPart) line: 1101 org.eclipse.e4.ui.workbench.renderers.swt.StackRenderer.closePart(org.eclipse.swt.widgets.Widget, boolean) line: 1111 org.eclipse.e4.ui.workbench.renderers.swt.StackRenderer.access$5(org.eclipse.e4.ui.workbench.renderers.swt.StackRenderer, org.eclipse.swt.widgets.Widget, boolean) line: 1093 org.eclipse.e4.ui.workbench.renderers.swt.StackRenderer$12.close(org.eclipse.swt.custom.CTabFolderEvent) line: 987 org.eclipse.swt.custom.CTabFolder.onMouse(org.eclipse.swt.widgets.Event) line: 1833 org.eclipse.swt.custom.CTabFolder$1.handleEvent(org.eclipse.swt.widgets.Event) line: 283 => the previous instance of SimpleTestView can be GCed even on this level of the stack org.eclipse.swt.widgets.EventTable.sendEvent(org.eclipse.swt.widgets.Event) line: 84 org.eclipse.swt.custom.CTabFolderCTabFolder(org.eclipse.swt.widgets.Widget).sendEvent(org.eclipse.swt.widgets.Event) line: 1058 org.eclipse.swt.widgets.Display.runDeferredEvents() line: 4170 org.eclipse.swt.widgets.Display.readAndDispatch() line: 3759 org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$9.run() line: 1113 org.eclipse.core.databinding.observable.Realm.runWithDefault(org.eclipse.core.databinding.observable.Realm, java.lang.Runnable) line: 332 org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.run(org.eclipse.e4.ui.model.application.MApplicationElement, org.eclipse.e4.core.contexts.IEclipseContext) line: 997 org.eclipse.e4.ui.internal.workbench.E4Workbench.createAndRunUI(org.eclipse.e4.ui.model.application.MApplicationElement) line: 138 org.eclipse.ui.internal.Workbench$5.run() line: 613 org.eclipse.core.databinding.observable.Realm.runWithDefault(org.eclipse.core.databinding.observable.Realm, java.lang.Runnable) line: 332 org.eclipse.ui.internal.Workbench.createAndRunWorkbench(org.eclipse.swt.widgets.Display, org.eclipse.ui.application.WorkbenchAdvisor) line: 567 org.eclipse.ui.PlatformUI.createAndRunWorkbench(org.eclipse.swt.widgets.Display, org.eclipse.ui.application.WorkbenchAdvisor) line: 150 org.eclipse.ui.internal.ide.application.IDEApplication.start(org.eclipse.equinox.app.IApplicationContext) line: 124 org.eclipse.equinox.internal.app.EclipseAppHandle.run(java.lang.Object) line: 196 org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(java.lang.Object) line: 109 org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(java.lang.Object) line: 80 org.eclipse.core.runtime.adaptor.EclipseStarter.run(java.lang.Object) line: 372 org.eclipse.core.runtime.adaptor.EclipseStarter.run(java.lang.String[], java.lang.Runnable) line: 226 sun.reflect.NativeMethodAccessorImpl.invoke0(java.lang.reflect.Method, java.lang.Object, java.lang.Object[]) line: not available [native method] sun.reflect.NativeMethodAccessorImpl.invoke(java.lang.Object, java.lang.Object[]) line: 60 sun.reflect.DelegatingMethodAccessorImpl.invoke(java.lang.Object, java.lang.Object[]) line: 37 java.lang.reflect.Method.invoke(java.lang.Object, java.lang.Object...) line: 611 org.eclipse.equinox.launcher.Main.invokeFramework(java.lang.String[], java.net.URL[]) line: 636 org.eclipse.equinox.launcher.Main.basicRun(java.lang.String[]) line: 591 org.eclipse.equinox.launcher.Main.run(java.lang.String[]) line: 1450 org.eclipse.equinox.launcher.Main.main(java.lang.String[]) line: 1426
Created attachment 236369 [details] path to gc roots 4.4M1 I have generated another path to gc roots when the view is closed and had a bit different than in this one in comment 6.
Mass move to 4.7 as M7 is approaching. Please move back in case you are planning to fix it for Neon.
This bug hasn't had any activity in quite some time. Maybe the problem got resolved, was a duplicate of something else, or became less pressing for some reason - or maybe it's still relevant but just hasn't been looked at yet. If you have further information on the current state of the bug, please add it. The information can be, for example, that the problem still occurs, that you still want the feature, that more information is needed, or that the bug is (for whatever reason) no longer relevant. -- The automated Eclipse Genie.
