When I run an maven project in eclipse,it always alert a tip like this:
!ENTRY org.eclipse.jface 4 2 2018-01-24 10:39:47.882
!MESSAGE Problems occurred when invoking code from plug-in: "org.eclipse.jface".
!STACK 0
java.lang.NullPointerException
at org.eclipse.jst.jee.ui.internal.navigator.web.WebAppProvider.getImage(WebAppProvider.java:99)
at org.eclipse.jst.jee.ui.internal.navigator.Web25LabelProvider.getImage(Web25LabelProvider.java:47)
at org.eclipse.ui.internal.navigator.NavigatorContentServiceLabelProvider.findImage(NavigatorContentServiceLabelProvider.java:199)
at org.eclipse.ui.internal.navigator.NavigatorContentServiceLabelProvider.getColumnImage(NavigatorContentServiceLabelProvider.java:107)
at org.eclipse.ui.internal.navigator.NavigatorContentServiceLabelProvider.getImage(NavigatorContentServiceLabelProvider.java:99)
at org.eclipse.ui.internal.navigator.NavigatorDecoratingLabelProvider$StyledLabelProviderAdapter.getImage(NavigatorDecoratingLabelProvider.java:57)
at org.eclipse.jface.viewers.DelegatingStyledCellLabelProvider.getImage(DelegatingStyledCellLabelProvider.java:195)
at org.eclipse.jface.viewers.DecoratingStyledCellLabelProvider.getImage(DecoratingStyledCellLabelProvider.java:168)
at org.eclipse.jface.viewers.DelegatingStyledCellLabelProvider.update(DelegatingStyledCellLabelProvider.java:121)
at org.eclipse.jface.viewers.DecoratingStyledCellLabelProvider.update(DecoratingStyledCellLabelProvider.java:131)
at org.eclipse.jface.viewers.ViewerColumn.refresh(ViewerColumn.java:141)
at org.eclipse.jface.viewers.AbstractTreeViewer.doUpdateItem(AbstractTreeViewer.java:946)
at org.eclipse.jface.viewers.AbstractTreeViewer$UpdateItemSafeRunnable.run(AbstractTreeViewer.java:117)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
at org.eclipse.ui.internal.JFaceUtil.lambda$0(JFaceUtil.java:44)
at org.eclipse.jface.util.SafeRunnable.run(SafeRunnable.java:173)
at org.eclipse.jface.viewers.AbstractTreeViewer.doUpdateItem(AbstractTreeViewer.java:1025)
at org.eclipse.jface.viewers.StructuredViewer$UpdateItemSafeRunnable.run(StructuredViewer.java:475)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
at org.eclipse.ui.internal.JFaceUtil.lambda$0(JFaceUtil.java:44)
at org.eclipse.jface.util.SafeRunnable.run(SafeRunnable.java:173)
at org.eclipse.jface.viewers.StructuredViewer.updateItem(StructuredViewer.java:2159)
at org.eclipse.jface.viewers.StructuredViewer.internalUpdate(StructuredViewer.java:2142)
at org.eclipse.jface.viewers.StructuredViewer.update(StructuredViewer.java:2083)
at org.eclipse.jface.viewers.ColumnViewer.update(ColumnViewer.java:542)
at org.eclipse.ui.navigator.CommonViewer.update(CommonViewer.java:512)
at org.eclipse.jface.viewers.StructuredViewer.update(StructuredViewer.java:2027)
at org.eclipse.jface.viewers.StructuredViewer.handleLabelProviderChanged(StructuredViewer.java:1203)
at org.eclipse.ui.navigator.CommonViewer.handleLabelProviderChanged(CommonViewer.java:237)
at org.eclipse.jface.viewers.ContentViewer$1.labelProviderChanged(ContentViewer.java:99)
at org.eclipse.jface.viewers.BaseLabelProvider$1.run(BaseLabelProvider.java:72)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
at org.eclipse.ui.internal.JFaceUtil.lambda$0(JFaceUtil.java:44)
at org.eclipse.jface.util.SafeRunnable.run(SafeRunnable.java:173)
at org.eclipse.jface.viewers.BaseLabelProvider.fireLabelProviderChanged(BaseLabelProvider.java:69)
at org.eclipse.jface.viewers.DecoratingStyledCellLabelProvider.lambda$0(DecoratingStyledCellLabelProvider.java:75)
at org.eclipse.ui.internal.decorators.DecoratorManager$1.run(DecoratorManager.java:374)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
at org.eclipse.ui.internal.decorators.DecoratorManager.fireListener(DecoratorManager.java:371)
at org.eclipse.ui.internal.decorators.DecorationScheduler$3.runInUIThread(DecorationScheduler.java:485)
at org.eclipse.ui.progress.UIJob.lambda$0(UIJob.java:95)
at org.eclipse.swt.widgets.RunnableLock.run(RunnableLock.java:37)
at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.java:182)
at org.eclipse.swt.widgets.Display.runAsyncMessages(Display.java:4213)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3820)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$5.run(PartRenderingEngine.java:1150)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:336)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.run(PartRenderingEngine.java:1039)
at org.eclipse.e4.ui.internal.workbench.E4Workbench.createAndRunUI(E4Workbench.java:153)
at org.eclipse.ui.internal.Workbench.lambda$3(Workbench.java:680)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:336)
at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:594)
at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:148)
at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:151)
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(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:653)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:590)
at org.eclipse.equinox.launcher.Main.run(Main.java:1499)
at org.eclipse.equinox.launcher.Main.main(Main.java:1472)
