java - Unable to edit .xhtml files on RAD 8.5/9.0 -

it showing following error:

java.lang.nullpointerexception     @ com.ibm.etools.references.internal.management.internalreferencemanager.expandlinktext(internalreferencemanager.java:473)     @ com.ibm.etools.references.management.referencemanager.expandlinktext(referencemanager.java:103)     @ com.ibm.etools.webedit.core.pdlinkfixupdelegates.linkutilbasedelegate.getabsurl(linkutilbasedelegate.java:85)     @ com.ibm.etools.webedit.viewer.utils.linkutilbase.getabsurl(linkutilbase.java:187)     @ com.ibm.etools.webedit.viewer.utils.linkutilbase.getabsurl(linkutilbase.java:206)     @ com.ibm.etools.webedit.viewer.utils.linkutilbase.getabsurl(linkutilbase.java:194)     @ com.ibm.etools.webedit.editparts.adapter.submodeladapterfactory.getrawresfilename(submodeladapterfactory.java:101)     @ com.ibm.etools.webedit.editparts.adapter.submodeladapter.getresfilename(submodeladapter.java:97)     @ com.ibm.etools.webedit.editparts.adapter.submodeladapter.getmodel(submodeladapter.java:52)     @ com.ibm.etools.webedit.editparts.elementeditpart.hassubmodel(elementeditpart.java:1801)     @ com.ibm.etools.webedit.render.internal.style.extended.htmlstylejspinclude.getdisplaytypefromelement(htmlstylejspinclude.java:45)     @ com.ibm.etools.xve.renderer.style.html.htmlstyleimpl.getdisplaytype(htmlstyleimpl.java:258)     @ com.ibm.etools.xve.renderer.figures.elementfigure.setstyle(elementfigure.java:1956)     @ com.ibm.etools.webedit.editparts.elementeditpart.initstyle(elementeditpart.java:745)     @ com.ibm.etools.webedit.editparts.elementeditpart.addnotify(elementeditpart.java:758)     @ org.eclipse.gef.editparts.abstracteditpart.addchild(abstracteditpart.java:212)     @ com.ibm.etools.webedit.editparts.nodeeditpart.refreshchildren(nodeeditpart.java:276)     @ com.ibm.etools.webedit.editparts.elementeditpart.refreshchildren(elementeditpart.java:1531)     @ org.eclipse.gef.editparts.abstracteditpart.refresh(abstracteditpart.java:726)     @ org.eclipse.gef.editparts.abstractgraphicaleditpart.refresh(abstractgraphicaleditpart.java:644)     @ org.eclipse.gef.editparts.abstracteditpart.addnotify(abstracteditpart.java:253)     @ org.eclipse.gef.editparts.abstractgraphicaleditpart.addnotify(abstractgraphicaleditpart.java:223)     @ com.ibm.etools.webedit.editparts.visiblenodeeditpart.addnotify(visiblenodeeditpart.java:216)     @ com.ibm.etools.webedit.editparts.elementeditpart.addnotify(elementeditpart.java:763)     @ org.eclipse.gef.editparts.abstracteditpart.addchild(abstracteditpart.java:212)     @ com.ibm.etools.webedit.editparts.nodeeditpart.refreshchildren(nodeeditpart.java:276)     @ com.ibm.etools.webedit.editparts.elementeditpart.refreshchildren(elementeditpart.java:1531)     @ org.eclipse.gef.editparts.abstracteditpart.refresh(abstracteditpart.java:726)     @ org.eclipse.gef.editparts.abstractgraphicaleditpart.refresh(abstractgraphicaleditpart.java:644)     @ org.eclipse.gef.editparts.abstracteditpart.addnotify(abstracteditpart.java:253)     @ org.eclipse.gef.editparts.abstractgraphicaleditpart.addnotify(abstractgraphicaleditpart.java:223)     @ com.ibm.etools.webedit.editparts.visiblenodeeditpart.addnotify(visiblenodeeditpart.java:216)     @ com.ibm.etools.webedit.editparts.elementeditpart.addnotify(elementeditpart.java:763)     @ org.eclipse.gef.editparts.abstracteditpart.addchild(abstracteditpart.java:212)     @ com.ibm.etools.webedit.editparts.nodeeditpart.refreshchildren(nodeeditpart.java:276)     @ com.ibm.etools.webedit.editparts.elementeditpart.refreshchildren(elementeditpart.java:1531)     @ org.eclipse.gef.editparts.abstracteditpart.refresh(abstracteditpart.java:726)     @ org.eclipse.gef.editparts.abstractgraphicaleditpart.refresh(abstractgraphicaleditpart.java:644)     @ org.eclipse.gef.editparts.abstracteditpart.addnotify(abstracteditpart.java:253)     @ org.eclipse.gef.editparts.abstractgraphicaleditpart.addnotify(abstractgraphicaleditpart.java:223)     @ com.ibm.etools.webedit.editparts.visiblenodeeditpart.addnotify(visiblenodeeditpart.java:216)     @ com.ibm.etools.webedit.editparts.elementeditpart.addnotify(elementeditpart.java:763)     @ org.eclipse.gef.editparts.abstracteditpart.addchild(abstracteditpart.java:212)     @ com.ibm.etools.webedit.editparts.nodeeditpart.refreshchildren(nodeeditpart.java:276)     @ com.ibm.etools.webedit.editparts.elementeditpart.refreshchildren(elementeditpart.java:1531)     @ org.eclipse.gef.editparts.abstracteditpart.refresh(abstracteditpart.java:726)     @ org.eclipse.gef.editparts.abstractgraphicaleditpart.refresh(abstractgraphicaleditpart.java:644)     @ org.eclipse.gef.editparts.abstracteditpart.addnotify(abstracteditpart.java:253)     @ org.eclipse.gef.editparts.abstractgraphicaleditpart.addnotify(abstractgraphicaleditpart.java:223)     @ com.ibm.etools.webedit.editparts.visiblenodeeditpart.addnotify(visiblenodeeditpart.java:216)     @ com.ibm.etools.webedit.editparts.elementeditpart.addnotify(elementeditpart.java:763)     @ org.eclipse.gef.editparts.abstracteditpart.addchild(abstracteditpart.java:212)     @ com.ibm.etools.webedit.editparts.nodeeditpart.refreshchildren(nodeeditpart.java:276)     @ com.ibm.etools.webedit.editparts.elementeditpart.refreshchildren(elementeditpart.java:1531)     @ org.eclipse.gef.editparts.abstracteditpart.refresh(abstracteditpart.java:726)     @ org.eclipse.gef.editparts.abstractgraphicaleditpart.refresh(abstractgraphicaleditpart.java:644)     @ org.eclipse.gef.editparts.abstracteditpart.addnotify(abstracteditpart.java:253)     @ org.eclipse.gef.editparts.abstractgraphicaleditpart.addnotify(abstractgraphicaleditpart.java:223)     @ com.ibm.etools.webedit.editparts.visiblenodeeditpart.addnotify(visiblenodeeditpart.java:216)     @ com.ibm.etools.webedit.editparts.elementeditpart.addnotify(elementeditpart.java:763)     @ org.eclipse.gef.editparts.abstracteditpart.addchild(abstracteditpart.java:212)     @ com.ibm.etools.webedit.editparts.nodeeditpart.refreshchildren(nodeeditpart.java:276)     @ com.ibm.etools.webedit.editparts.offrenderingeditpart.refreshchildren(offrenderingeditpart.java:638)     @ org.eclipse.gef.editparts.abstracteditpart.refresh(abstracteditpart.java:726)     @ org.eclipse.gef.editparts.abstractgraphicaleditpart.refresh(abstractgraphicaleditpart.java:644)     @ org.eclipse.gef.editparts.abstracteditpart.addnotify(abstracteditpart.java:253)     @ org.eclipse.gef.editparts.abstractgraphicaleditpart.addnotify(abstractgraphicaleditpart.java:223)     @ org.eclipse.gef.editparts.abstracteditpart.addchild(abstracteditpart.java:212)     @ com.ibm.etools.webedit.editparts.documenteditpart.refreshchildren(documenteditpart.java:1102)     @ org.eclipse.gef.editparts.abstracteditpart.refresh(abstracteditpart.java:726)     @ org.eclipse.gef.editparts.abstractgraphicaleditpart.refresh(abstractgraphicaleditpart.java:644)     @ org.eclipse.gef.editparts.abstracteditpart.addnotify(abstracteditpart.java:253)     @ org.eclipse.gef.editparts.abstractgraphicaleditpart.addnotify(abstractgraphicaleditpart.java:223)     @ com.ibm.etools.webedit.editparts.documenteditpart.addnotify(documenteditpart.java:739)     @ org.eclipse.gef.editparts.abstracteditpart.addchild(abstracteditpart.java:212)     @ org.eclipse.gef.editparts.simplerooteditpart.setcontents(simplerooteditpart.java:105)     @ com.ibm.etools.webedit.editparts.htmlgraphicalrooteditpart.setcontents(htmlgraphicalrooteditpart.java:228)     @ org.eclipse.gef.ui.parts.abstracteditpartviewer.setcontents(abstracteditpartviewer.java:617)     @ com.ibm.etools.webedit.editparts.htmlgraphicalviewerimpl.setcontents(htmlgraphicalviewerimpl.java:995)     @ com.ibm.etools.webedit.editor.internal.page.design.wysiwygview.setmodel(wysiwygview.java:881)     @ com.ibm.etools.webedit.editor.internal.page.design.htmldesignpage.setmodel(htmldesignpage.java:1567)     @ com.ibm.etools.webedit.editor.htmleditor.createdesignpane(htmleditor.java:1559)     @ com.ibm.etools.webedit.editor.htmleditor.access$21(htmleditor.java:1551)     @ com.ibm.etools.webedit.editor.htmleditor$splitpanecontainer.createpane(htmleditor.java:6149)     @ com.ibm.etools.webedit.editor.internal.pane.pagedesignerpanecontainerfortwo.createandaddpane(pagedesignerpanecontainerfortwo.java:355)     @ com.ibm.etools.webedit.editor.internal.pane.pagedesignerpanecontainerfortwo.createpanecontainer(pagedesignerpanecontainerfortwo.java:78)     @ com.ibm.etools.webedit.editor.htmleditor$splitpanecontainer.createpanecontainer(htmleditor.java:6136)     @ com.ibm.etools.webedit.editor.htmleditor$mypanemanager.createtabs(htmleditor.java:6222)     @ com.ibm.etools.webedit.editor.internal.pane.multipaneeditorpart.createpages(multipaneeditorpart.java:293)     @ com.ibm.etools.webedit.editor.htmleditor.createpages(htmleditor.java:1598)     @ org.eclipse.ui.part.multipageeditorpart.createpartcontrol(multipageeditorpart.java:358)     @ org.eclipse.ui.internal.e4.compatibility.compatibilitypart.createpartcontrol(compatibilitypart.java:138)     @ org.eclipse.ui.internal.e4.compatibility.compatibilityeditor.createpartcontrol(compatibilityeditor.java:96)     @ org.eclipse.ui.internal.e4.compatibility.compatibilitypart.create(compatibilitypart.java:313)     @ sun.reflect.nativemethodaccessorimpl.invoke0(native method)     @ sun.reflect.nativemethodaccessorimpl.invoke(nativemethodaccessorimpl.java:88)     @ sun.reflect.delegatingmethodaccessorimpl.invoke(delegatingmethodaccessorimpl.java:55)     @ java.lang.reflect.method.invoke(method.java:613)     @ org.eclipse.e4.core.internal.di.methodrequestor.execute(methodrequestor.java:56)     @ org.eclipse.e4.core.internal.di.injectorimpl.processannotated(injectorimpl.java:861)     @ org.eclipse.e4.core.internal.di.injectorimpl.processannotated(injectorimpl.java:841)     @ org.eclipse.e4.core.internal.di.injectorimpl.inject(injectorimpl.java:113)     @ org.eclipse.e4.core.internal.di.injectorimpl.internalmake(injectorimpl.java:321)     @ org.eclipse.e4.core.internal.di.injectorimpl.make(injectorimpl.java:242)     @ org.eclipse.e4.core.contexts.contextinjectionfactory.make(contextinjectionfactory.java:161)     @ org.eclipse.e4.ui.internal.workbench.reflectioncontributionfactory.createfrombundle(reflectioncontributionfactory.java:102)     @ org.eclipse.e4.ui.internal.workbench.reflectioncontributionfactory.docreate(reflectioncontributionfactory.java:71)     @ org.eclipse.e4.ui.internal.workbench.reflectioncontributionfactory.create(reflectioncontributionfactory.java:53)     @ org.eclipse.e4.ui.workbench.renderers.swt.contributedpartrenderer.createwidget(contributedpartrenderer.java:141)     @ org.eclipse.e4.ui.internal.workbench.swt.partrenderingengine.createwidget(partrenderingengine.java:894)     @ org.eclipse.e4.ui.internal.workbench.swt.partrenderingengine.safecreategui(partrenderingengine.java:629)     @ org.eclipse.e4.ui.internal.workbench.swt.partrenderingengine.safecreategui(partrenderingengine.java:731)     @ org.eclipse.e4.ui.internal.workbench.swt.partrenderingengine.access$2(partrenderingengine.java:702)     @ org.eclipse.e4.ui.internal.workbench.swt.partrenderingengine$7.run(partrenderingengine.java:696)     @ org.eclipse.core.runtime.saferunner.run(saferunner.java:42)     @ org.eclipse.e4.ui.internal.workbench.swt.partrenderingengine.creategui(partrenderingengine.java:681)     @ org.eclipse.e4.ui.internal.workbench.partserviceimpl$1.handleevent(partserviceimpl.java:92)     @ org.eclipse.e4.ui.services.internal.events.uieventhandler$1.run(uieventhandler.java:41)     @ org.eclipse.swt.widgets.synchronizer.syncexec(synchronizer.java:180)     @ org.eclipse.ui.internal.uisynchronizer.syncexec(uisynchronizer.java:150)     @ org.eclipse.swt.widgets.display.syncexec(display.java:4687)     @ org.eclipse.e4.ui.internal.workbench.swt.e4application$1.syncexec(e4application.java:187)     @ org.eclipse.e4.ui.services.internal.events.uieventhandler.handleevent(uieventhandler.java:38)     @ org.eclipse.equinox.internal.event.eventhandlerwrapper.handleevent(eventhandlerwrapper.java:197)     @ org.eclipse.equinox.internal.event.eventhandlertracker.dispatchevent(eventhandlertracker.java:197)     @ org.eclipse.equinox.internal.event.eventhandlertracker.dispatchevent(eventhandlertracker.java:1)     @ org.eclipse.osgi.framework.eventmgr.eventmanager.dispatchevent(eventmanager.java:230)     @ org.eclipse.osgi.framework.eventmgr.listenerqueue.dispatcheventsynchronous(listenerqueue.java:148)     @ org.eclipse.equinox.internal.event.eventadminimpl.dispatchevent(eventadminimpl.java:135)     @ org.eclipse.equinox.internal.event.eventadminimpl.sendevent(eventadminimpl.java:78)     @ org.eclipse.equinox.internal.event.eventcomponent.sendevent(eventcomponent.java:39)     @ org.eclipse.e4.ui.services.internal.events.eventbroker.send(eventbroker.java:80)     @ org.eclipse.e4.ui.internal.workbench.uieventpublisher.notifychanged(uieventpublisher.java:58)     @ org.eclipse.emf.common.notify.impl.basicnotifierimpl.enotify(basicnotifierimpl.java:374)     @ org.eclipse.e4.ui.model.application.ui.impl.elementcontainerimpl.setselectedelement(elementcontainerimpl.java:171)     @ org.eclipse.e4.ui.internal.workbench.modelserviceimpl.showelementinwindow(modelserviceimpl.java:422)     @ org.eclipse.e4.ui.internal.workbench.modelserviceimpl.bringtotop(modelserviceimpl.java:389)     @ org.eclipse.e4.ui.internal.workbench.partserviceimpl.delegatebringtotop(partserviceimpl.java:606)     @ org.eclipse.e4.ui.internal.workbench.partserviceimpl.bringtotop(partserviceimpl.java:332)     @ org.eclipse.e4.ui.internal.workbench.partserviceimpl.showpart(partserviceimpl.java:1029)     @ org.eclipse.ui.internal.workbenchpage.busyopeneditor(workbenchpage.java:3047)     @ org.eclipse.ui.internal.workbenchpage.access$22(workbenchpage.java:2969)     @ org.eclipse.ui.internal.workbenchpage$8.run(workbenchpage.java:2951)     @ org.eclipse.swt.custom.busyindicator.showwhile(busyindicator.java:70)     @ org.eclipse.ui.internal.workbenchpage.openeditor(workbenchpage.java:2947)     @ org.eclipse.ui.internal.workbenchpage.openeditor(workbenchpage.java:2911)     @ org.eclipse.ui.internal.workbenchpage.openeditor(workbenchpage.java:2902)     @ org.eclipse.ui.ide.ide.openeditor(ide.java:655)     @ org.eclipse.ui.ide.ide.openeditor(ide.java:614)     @ org.eclipse.ui.internal.ide.handlers.openresourcehandler.execute(openresourcehandler.java:129)     @ org.eclipse.ui.internal.ide.handlers.openresourcehandler.run(openresourcehandler.java:181)     @ org.eclipse.ui.internal.handlers.actiondelegatehandlerproxy.execute(actiondelegatehandlerproxy.java:295)     @ org.eclipse.ui.internal.handlers.e4handlerproxy.execute(e4handlerproxy.java:81)     @ sun.reflect.nativemethodaccessorimpl.invoke0(native method)     @ sun.reflect.nativemethodaccessorimpl.invoke(nativemethodaccessorimpl.java:88)     @ sun.reflect.delegatingmethodaccessorimpl.invoke(delegatingmethodaccessorimpl.java:55)     @ java.lang.reflect.method.invoke(method.java:613)     @ org.eclipse.e4.core.internal.di.methodrequestor.execute(methodrequestor.java:56)     @ org.eclipse.e4.core.internal.di.injectorimpl.invokeusingclass(injectorimpl.java:231)     @ org.eclipse.e4.core.internal.di.injectorimpl.invoke(injectorimpl.java:212)     @ org.eclipse.e4.core.contexts.contextinjectionfactory.invoke(contextinjectionfactory.java:131)     @ org.eclipse.e4.core.commands.internal.handlerserviceimpl.executehandler(handlerserviceimpl.java:171)     @ org.eclipse.e4.ui.bindings.keys.keybindingdispatcher.executecommand(keybindingdispatcher.java:277)     @ org.eclipse.e4.ui.bindings.keys.keybindingdispatcher.press(keybindingdispatcher.java:496)     @ org.eclipse.e4.ui.bindings.keys.keybindingdispatcher.processkeyevent(keybindingdispatcher.java:547)     @ org.eclipse.e4.ui.bindings.keys.keybindingdispatcher.filterkeysequencebindings(keybindingdispatcher.java:368)     @ org.eclipse.e4.ui.bindings.keys.keybindingdispatcher.access$0(keybindingdispatcher.java:314)     @ org.eclipse.e4.ui.bindings.keys.keybindingdispatcher$keydownfilter.handleevent(keybindingdispatcher.java:83)     @ org.eclipse.swt.widgets.eventtable.sendevent(eventtable.java:84)     @ org.eclipse.swt.widgets.display.filterevent(display.java:1262)     @ org.eclipse.swt.widgets.widget.sendevent(widget.java:1052)     @ org.eclipse.swt.widgets.widget.sendevent(widget.java:1077)     @ org.eclipse.swt.widgets.widget.sendevent(widget.java:1062)     @ org.eclipse.swt.widgets.widget.sendkeyevent(widget.java:1104)     @ org.eclipse.swt.widgets.widget.sendkeyevent(widget.java:1100)     @ org.eclipse.swt.widgets.widget.wmchar(widget.java:1521)     @ org.eclipse.swt.widgets.control.wm_char(control.java:4640)     @ org.eclipse.swt.widgets.tree.wm_char(tree.java:5981)     @ org.eclipse.swt.widgets.control.windowproc(control.java:4528)     @ org.eclipse.swt.widgets.tree.windowproc(tree.java:5977)     @ org.eclipse.swt.widgets.display.windowproc(display.java:4976)     @ org.eclipse.swt.internal.win32.os.dispatchmessagew(native method)     @ org.eclipse.swt.internal.win32.os.dispatchmessage(os.java:2546)     @ org.eclipse.swt.widgets.display.readanddispatch(display.java:3756)     @ org.eclipse.e4.ui.internal.workbench.swt.partrenderingengine$9.run(partrenderingengine.java:1053)     @ org.eclipse.core.databinding.observable.realm.runwithdefault(realm.java:332)     @ org.eclipse.e4.ui.internal.workbench.swt.partrenderingengine.run(partrenderingengine.java:942)     @ org.eclipse.e4.ui.internal.workbench.e4workbench.createandrunui(e4workbench.java:86)     @ org.eclipse.ui.internal.workbench$5.run(workbench.java:588)     @ org.eclipse.core.databinding.observable.realm.runwithdefault(realm.java:332)     @ org.eclipse.ui.internal.workbench.createandrunworkbench(workbench.java:543)     @ org.eclipse.ui.platformui.createandrunworkbench(platformui.java:149)     @ org.eclipse.ui.internal.ide.application.ideapplication.start(ideapplication.java:124)     @ org.eclipse.equinox.internal.app.eclipseapphandle.run(eclipseapphandle.java:196)     @ org.eclipse.core.runtime.internal.adaptor.eclipseapplauncher.runapplication(eclipseapplauncher.java:110)     @ org.eclipse.core.runtime.internal.adaptor.eclipseapplauncher.start(eclipseapplauncher.java:79)     @ org.eclipse.core.runtime.adaptor.eclipsestarter.run(eclipsestarter.java:353)     @ org.eclipse.core.runtime.adaptor.eclipsestarter.run(eclipsestarter.java:180)     @ sun.reflect.nativemethodaccessorimpl.invoke0(native method)     @ sun.reflect.nativemethodaccessorimpl.invoke(nativemethodaccessorimpl.java:88)     @ sun.reflect.delegatingmethodaccessorimpl.invoke(delegatingmethodaccessorimpl.java:55)     @ java.lang.reflect.method.invoke(method.java:613)     @ org.eclipse.equinox.launcher.main.invokeframework(main.java:629)     @ org.eclipse.equinox.launcher.main.basicrun(main.java:584)     @ org.eclipse.equinox.launcher.main.run(main.java:1438)     @ org.eclipse.equinox.launcher.main.main(main.java:1414)