一保存就报错，但是不影响效果，我删了workspace重建还是不行，网上搜不到解决方法，求助
org.eclipse.jface
Error
Mon Oct 23 14:41:48 CST 2017
Problems occurred when invoking code from plug-in: "org.eclipse.jface".
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$StyledLabelProviderAdapter.getImage(NavigatorDecoratingLabelProvider.java:57)
at org.eclipse.jface.viewers.DelegatingStyledCellLabelProvider.getImage(DelegatingStyledCellLabelProvider.java:195)
at org.eclipse.jface.viewers.DecoratingStyledCellLabelProvider.getImage(DecoratingStyledCellLabelProvider.java:173)
at org.eclipse.jface.viewers.DelegatingStyledCellLabelProvider.update(DelegatingStyledCellLabelProvider.java:121)
at org.eclipse.jface.viewers.DecoratingStyledCellLabelProvider.update(DecoratingStyledCellLabelProvider.java:136)
at org.eclipse.jface.viewers.ViewerColumn.refresh(ViewerColumn.java:154)
at org.eclipse.jface.viewers.AbstractTreeViewer.doUpdateItem(AbstractTreeViewer.java:949)
at org.eclipse.jface.viewers.AbstractTreeViewer$UpdateItemSafeRunnable.run(AbstractTreeViewer.java:114)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
at org.eclipse.ui.internal.JFaceUtil$1.run(JFaceUtil.java:50)
at org.eclipse.jface.util.SafeRunnable.run(SafeRunnable.java:173)
at org.eclipse.jface.viewers.AbstractTreeViewer.doUpdateItem(AbstractTreeViewer.java:1029)
at org.eclipse.jface.viewers.StructuredViewer$UpdateItemSafeRunnable.run(StructuredViewer.java:473)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
at org.eclipse.ui.internal.JFaceUtil$1.run(JFaceUtil.java:50)
at org.eclipse.jface.util.SafeRunnable.run(SafeRunnable.java:173)
at org.eclipse.jface.viewers.StructuredViewer.updateItem(StructuredViewer.java:2176)
at org.eclipse.jface.viewers.AbstractTreeViewer.createTreeItem(AbstractTreeViewer.java:843)
at org.eclipse.jface.viewers.AbstractTreeViewer$1.run(AbstractTreeViewer.java:818)
at org.eclipse.swt.custom.BusyIndicator.showWhile(BusyIndicator.java:70)
at org.eclipse.jface.viewers.AbstractTreeViewer.createChildren(AbstractTreeViewer.java:791)
at org.eclipse.jface.viewers.TreeViewer.createChildren(TreeViewer.java:611)
at org.eclipse.jface.viewers.AbstractTreeViewer.createChildren(AbstractTreeViewer.java:762)
at org.eclipse.jface.viewers.AbstractTreeViewer.handleTreeExpand(AbstractTreeViewer.java:1493)
at org.eclipse.jface.viewers.TreeViewer.handleTreeExpand(TreeViewer.java:903)
at org.eclipse.jface.viewers.AbstractTreeViewer$4.treeExpanded(AbstractTreeViewer.java:1505)
at org.eclipse.swt.widgets.TypedListener.handleEvent(TypedListener.java:132)
at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
at org.eclipse.swt.widgets.Display.sendEvent(Display.java:4362)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1113)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1137)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1122)
at org.eclipse.swt.widgets.Tree.wmNotifyChild(Tree.java:7633)
at org.eclipse.swt.widgets.Control.wmNotify(Control.java:5704)
at org.eclipse.swt.widgets.Composite.wmNotify(Composite.java:1956)
at org.eclipse.swt.widgets.Control.WM_NOTIFY(Control.java:5256)
at org.eclipse.swt.widgets.Control.windowProc(Control.java:4732)
at org.eclipse.swt.widgets.Display.windowProc(Display.java:5050)
at org.eclipse.swt.internal.win32.OS.CallWindowProcW(Native Method)
at org.eclipse.swt.internal.win32.OS.CallWindowProc(OS.java:2443)
at org.eclipse.swt.widgets.Tree.callWindowProc(Tree.java:1553)
at org.eclipse.swt.widgets.Tree.WM_LBUTTONDOWN(Tree.java:6501)
at org.eclipse.swt.widgets.Control.windowProc(Control.java:4712)
at org.eclipse.swt.widgets.Tree.windowProc(Tree.java:6024)
at org.eclipse.swt.widgets.Display.windowProc(Display.java:5050)
at org.eclipse.swt.internal.win32.OS.DispatchMessageW(Native Method)
at org.eclipse.swt.internal.win32.OS.DispatchMessage(OS.java:2549)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3767)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$4.run(PartRenderingEngine.java:1127)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:337)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.run(PartRenderingEngine.java:1018)
at org.eclipse.e4.ui.internal.workbench.E4Workbench.createAndRunUI(E4Workbench.java:156)
at org.eclipse.ui.internal.Workbench$5.run(Workbench.java:694)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:337)
at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:606)
at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:150)
at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:139)
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:380)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:235)
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:606)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:669)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:608)
at org.eclipse.equinox.launcher.Main.run(Main.java:1515)
