NullPointerException

[yanan]

Copy from error log:
java.util.concurrent.ExecutionException: java.lang.NullPointerException
at java.util.concurrent.CompletableFuture.reportGet(CompletableFuture.java:357)
at java.util.concurrent.CompletableFuture.get(CompletableFuture.java:1915)
at org.eclipse.ui.internal.navigator.resources.nested.NestedProjectsLabelProvider.getHighestProblemSeverity(NestedProjectsLabelProvider.java:254)
at org.eclipse.ui.internal.navigator.resources.workbench.ResourceExtensionLabelProvider.decorateImage(ResourceExtensionLabelProvider.java:68)
at org.eclipse.ui.model.WorkbenchLabelProvider.getImage(WorkbenchLabelProvider.java:189)
at org.eclipse.ui.internal.navigator.NavigatorContentServiceLabelProvider.findImage(NavigatorContentServiceLabelProvider.java:202)
at org.eclipse.ui.internal.navigator.NavigatorContentServiceLabelProvider.getColumnImage(NavigatorContentServiceLabelProvider.java:110)
at org.eclipse.ui.internal.navigator.NavigatorContentServiceLabelProvider.getImage(NavigatorContentServiceLabelProvider.java:102)
at org.eclipse.ui.internal.navigator.NavigatorDecoratingLabelProvider$StyledLabelProviderAdapter.getImage(NavigatorDecoratingLabelProvider.java:60)
at org.eclipse.jface.viewers.DelegatingStyledCellLabelProvider.getImage(DelegatingStyledCellLabelProvider.java:198)
at org.eclipse.jface.viewers.DecoratingStyledCellLabelProvider.getImage(DecoratingStyledCellLabelProvider.java:171)
at org.eclipse.jface.viewers.DelegatingStyledCellLabelProvider.update(DelegatingStyledCellLabelProvider.java:124)
at org.eclipse.jface.viewers.DecoratingStyledCellLabelProvider.update(DecoratingStyledCellLabelProvider.java:134)
at org.eclipse.jface.viewers.ViewerColumn.refresh(ViewerColumn.java:144)
at org.eclipse.jface.viewers.AbstractTreeViewer.doUpdateItem(AbstractTreeViewer.java:946)
at org.eclipse.jface.viewers.AbstractTreeViewer$UpdateItemSafeRunnable.run(AbstractTreeViewer.java:120)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:45)
at org.eclipse.ui.internal.JFaceUtil.lambda$0(JFaceUtil.java:47)
at org.eclipse.jface.util.SafeRunnable.run(SafeRunnable.java:176)
at org.eclipse.jface.viewers.AbstractTreeViewer.doUpdateItem(AbstractTreeViewer.java:1025)
at org.eclipse.ui.navigator.CommonViewer.doUpdateItem(CommonViewer.java:404)
at org.eclipse.ui.internal.navigator.resources.ResourceToItemsMapper.updateItem(ResourceToItemsMapper.java:153)
at org.eclipse.ui.internal.navigator.resources.ResourceToItemsMapper.objectChanged(ResourceToItemsMapper.java:141)
at org.eclipse.ui.navigator.CommonViewer.handleLabelProviderChanged(CommonViewer.java:228)
at org.eclipse.jface.viewers.ContentViewer$1.labelProviderChanged(ContentViewer.java:102)
at org.eclipse.jface.viewers.BaseLabelProvider$1.run(BaseLabelProvider.java:75)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:45)
at org.eclipse.ui.internal.JFaceUtil.lambda$0(JFaceUtil.java:47)
at org.eclipse.jface.util.SafeRunnable.run(SafeRunnable.java:176)
at org.eclipse.jface.viewers.BaseLabelProvider.fireLabelProviderChanged(BaseLabelProvider.java:72)
at org.eclipse.jface.viewers.DecoratingStyledCellLabelProvider.lambda$0(DecoratingStyledCellLabelProvider.java:78)
at org.eclipse.ui.internal.decorators.DecoratorManager$1.run(DecoratorManager.java:377)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:45)
at org.eclipse.ui.internal.decorators.DecoratorManager.fireListener(DecoratorManager.java:374)
at org.eclipse.ui.internal.decorators.DecorationScheduler$3.runInUIThread(DecorationScheduler.java:488)
at org.eclipse.ui.progress.UIJob.lambda$0(UIJob.java:98)
at org.eclipse.swt.widgets.RunnableLock.run(RunnableLock.java:40)
at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.java:185)
at org.eclipse.swt.widgets.Display.runAsyncMessages(Display.java:4906)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:4475)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$5.run(PartRenderingEngine.java:1173)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:339)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.run(PartRenderingEngine.java:1062)
at org.eclipse.e4.ui.internal.workbench.E4Workbench.createAndRunUI(E4Workbench.java:156)
at org.eclipse.ui.internal.Workbench.lambda$3(Workbench.java:636)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:339)
at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:563)
at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:151)
at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:155)
at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:203)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:137)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:107)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:400)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:255)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:659)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:595)
at org.eclipse.equinox.launcher.Main.run(Main.java:1501)
at org.eclipse.equinox.launcher.Main.main(Main.java:1474)
Caused by: java.lang.NullPointerException
at org.eclipse.ui.internal.navigator.resources.nested.NestedProjectsLabelProvider$ProblemsModelSupplier.lambda$0(NestedProjectsLabelProvider.java:155)
at java.util.Collection.removeIf(Collection.java:414)
at org.eclipse.ui.internal.navigator.resources.nested.NestedProjectsLabelProvider$ProblemsModelSupplier.removeFromCache(NestedProjectsLabelProvider.java:154)
at org.eclipse.ui.internal.navigator.resources.nested.NestedProjectsLabelProvider$ProblemsModelSupplier.get(NestedProjectsLabelProvider.java:114)
at org.eclipse.ui.internal.navigator.resources.nested.NestedProjectsLabelProvider$ProblemsModelSupplier.get(NestedProjectsLabelProvider.java:1)
at java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1590)
at java.util.concurrent.CompletableFuture$AsyncSupply.exec(CompletableFuture.java:1582)
at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:289)
at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1056)
at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1692)
at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:157)