Hello,

I'm having the same problem.  I solved it a month or so by abandoning my eclipse workspace and creating a new one, but that is a frustrating way to go.  It's happening again...

!ENTRY org.eclipse.core.jobs 4 2 2014-11-18 07:14:35.469
!MESSAGE An internal error occurred during: "Synchronizing Work Item Read State With Change Events".
!STACK 0
java.lang.NoClassDefFoundError: com.ibm.team.feed.core.FeedManager$Holder (initialization failure)
    at java.lang.J9VMInternals.initialize(J9VMInternals.java:177)
    at com.ibm.team.feed.core.FeedManager.getDefault(FeedManager.java:175)
    at com.ibm.team.workitem.rcp.ui.internal.ReadStateTrackerFactory$1.runProtected(ReadStateTrackerFactory.java:74)
    at com.ibm.team.foundation.client.util.FoundationJob.run(FoundationJob.java:68)
    at org.eclipse.core.internal.jobs.Worker.run(Worker.java:54)
Caused by: java.lang.ArrayIndexOutOfBoundsException
    at org.apache.xerces.impl.io.UTF8Reader.read(Unknown Source)
    at org.apache.xerces.impl.XMLEntityScanner.load(Unknown Source)
    at org.apache.xerces.impl.XMLEntityScanner.skipSpaces(Unknown Source)
    at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanStartElement(Unknown Source)
    at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl$FragmentContentDispatcher.dispatch(Unknown Source)
    at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanDocument(Unknown Source)
    at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
    at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
    at org.apache.xerces.parsers.XMLParser.parse(Unknown Source)
    at org.apache.xerces.parsers.AbstractSAXParser.parse(Unknown Source)
    at org.apache.xerces.jaxp.SAXParserImpl$JAXPSAXParser.parse(Unknown Source)
    at org.apache.xerces.jaxp.SAXParserImpl.parse(Unknown Source)
    at org.eclipse.emf.ecore.xmi.impl.XMLLoadImpl.load(XMLLoadImpl.java:181)
    at org.eclipse.emf.ecore.xmi.impl.XMLResourceImpl.doLoad(XMLResourceImpl.java:242)
    at org.eclipse.emf.ecore.resource.impl.ResourceImpl.load(ResourceImpl.java:1511)
    at org.eclipse.emf.ecore.resource.impl.ResourceImpl.load(ResourceImpl.java:1290)
    at com.ibm.team.foundation.rcp.core.internal.EMFStorageHelper.loadModel(EMFStorageHelper.java:39)
    at com.ibm.team.feed.core.FeedManager.getModel(FeedManager.java:198)
    at com.ibm.team.feed.core.FeedManager.access$3(FeedManager.java:194)
    at com.ibm.team.feed.core.FeedManager$Holder.<clinit>(FeedManager.java:171)
    at java.lang.J9VMInternals.initializeImpl(Native Method)
    at java.lang.J9VMInternals.initialize(J9VMInternals.java:237)
    at com.ibm.team.feed.core.FeedManager.getDefault(FeedManager.java:175)
    at com.ibm.team.process.internal.rcp.ui.teamnavigator.feeds.SubscriptionsDomain.<init>(SubscriptionsDomain.java:109)
    at java.lang.J9VMInternals.newInstanceImpl(Native Method)
    at java.lang.Class.newInstance(Class.java:1628)
    at org.eclipse.core.internal.registry.osgi.RegistryStrategyOSGI.createExecutableExtension(RegistryStrategyOSGI.java:184)
    at org.eclipse.core.internal.registry.ExtensionRegistry.createExecutableExtension(ExtensionRegistry.java:905)
    at org.eclipse.core.internal.registry.ConfigurationElement.createExecutableExtension(ConfigurationElement.java:243)
    at org.eclipse.core.internal.registry.ConfigurationElementHandle.createExecutableExtension(ConfigurationElementHandle.java:55)
    at com.ibm.team.process.internal.rcp.ui.DomainManager.elementAdded(DomainManager.java:214)
    at com.ibm.team.foundation.rcp.core.extensionpoint.ExtensionPointHandler.processExtension(ExtensionPointHandler.java:89)
    at com.ibm.team.foundation.rcp.core.extensionpoint.ExtensionPointHandler.access$0(ExtensionPointHandler.java:79)
    at com.ibm.team.foundation.rcp.core.extensionpoint.ExtensionPointHandler$1.added(ExtensionPointHandler.java:38)
    at com.ibm.team.foundation.rcp.core.extensionpoint.ExtensionPointManager.notifyMonitor(ExtensionPointManager.java:91)
    at com.ibm.team.foundation.rcp.core.extensionpoint.ExtensionPointManager.loadExtensionPoint(ExtensionPointManager.java:165)
    at com.ibm.team.foundation.rcp.core.extensionpoint.ExtensionPointManager.addMonitor(ExtensionPointManager.java:134)
    at com.ibm.team.foundation.rcp.core.extensionpoint.ExtensionPointHandler.init(ExtensionPointHandler.java:63)
    at com.ibm.team.process.internal.rcp.ui.DomainManager.<init>(DomainManager.java:64)
    at com.ibm.team.process.internal.rcp.ui.DomainNavigator.createPartControl(DomainNavigator.java:172)
    at com.ibm.team.process.internal.rcp.ui.TeamArtifactsNavigator.createPartControl(TeamArtifactsNavigator.java:77)
    at org.eclipse.ui.internal.ViewReference.createPartHelper(ViewReference.java:375)
    at org.eclipse.ui.internal.ViewReference.createPart(ViewReference.java:229)
    at org.eclipse.ui.internal.WorkbenchPartReference.getPart(WorkbenchPartReference.java:595)
    at org.eclipse.ui.internal.PartPane.setVisible(PartPane.java:313)
    at org.eclipse.ui.internal.ViewPane.setVisible(ViewPane.java:534)
    at org.eclipse.ui.internal.presentations.PresentablePart.setVisible(PresentablePart.java:180)
    at org.eclipse.ui.internal.presentations.util.PresentablePartFolder.select(PresentablePartFolder.java:270)
    at org.eclipse.ui.internal.presentations.util.LeftToRightTabOrder.select(LeftToRightTabOrder.java:65)
    at org.eclipse.ui.internal.presentations.util.TabbedStackPresentation.selectPart(TabbedStackPresentation.java:473)
    at org.eclipse.ui.internal.PartStack.refreshPresentationSelection(PartStack.java:1245)
    at org.eclipse.ui.internal.PartStack.createControl(PartStack.java:662)
    at org.eclipse.ui.internal.PartStack.createControl(PartStack.java:570)
    at org.eclipse.ui.internal.PartSashContainer.createControl(PartSashContainer.java:568)
    at org.eclipse.ui.internal.PerspectiveHelper.activate(PerspectiveHelper.java:272)
    at org.eclipse.ui.internal.Perspective.onActivate(Perspective.java:981)
    at org.eclipse.ui.internal.WorkbenchPage.onActivate(WorkbenchPage.java:2714)
    at org.eclipse.ui.internal.WorkbenchWindow$28.run(WorkbenchWindow.java:3030)
    at org.eclipse.swt.custom.BusyIndicator.showWhile(BusyIndicator.java:70)
    at org.eclipse.ui.internal.WorkbenchWindow.setActivePage(WorkbenchWindow.java:3011)
    at org.eclipse.ui.internal.WorkbenchWindow$21.runWithException(WorkbenchWindow.java:2297)
    at org.eclipse.ui.internal.StartupThreading$StartupRunnable.run(StartupThreading.java:31)
    at org.eclipse.swt.widgets.RunnableLock.run(RunnableLock.java:35)
    at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.java:135)
    at org.eclipse.swt.widgets.Display.runAsyncMessages(Display.java:4140)
    at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3757)
    at org.eclipse.ui.application.WorkbenchAdvisor.openWindows(WorkbenchAdvisor.java:803)
    at org.eclipse.ui.internal.Workbench$33.runWithException(Workbench.java:1600)
    at org.eclipse.ui.internal.StartupThreading$StartupRunnable.run(StartupThreading.java:31)
    at org.eclipse.swt.widgets.RunnableLock.run(RunnableLock.java:35)
    at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.java:135)
    at org.eclipse.swt.widgets.Display.runAsyncMessages(Display.java:4140)
    at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3757)
    at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:2609)
    at org.eclipse.ui.internal.Workbench.access$4(Workbench.java:2499)
    at org.eclipse.ui.internal.Workbench$7.run(Workbench.java:679)
    at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
    at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:668)
    at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149)
    at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:123)
    at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196)
    at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:110)
    at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:79)
    at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:344)
    at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:179)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:94)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:55)
    at java.lang.reflect.Method.invoke(Method.java:619)
    at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:622)
    at org.eclipse.equinox.launcher.Main.basicRun(Main.java:577)
    at org.eclipse.equinox.launcher.Main.run(Main.java:1410)
    at org.eclipse.equinox.launcher.Main.main(Main.java:1386)