Hybris backoffice error

java.lang.NullPointerException

        at com.hybris.backoffice.cockpitng.modules.BackofficeModuleConnector.getWidgetTreeContent(BackofficeModuleConnector.java:90)

        at com.hybris.cockpitng.modules.persistence.impl.XmlModuleAwarePersistenceService.loadWidgets(XmlModuleAwarePersistenceService.java:135)

        at com.hybris.cockpitng.core.persistence.impl.XMLWidgetPersistenceService.loadWidgetTree(XMLWidgetPersistenceService.java:95)

        at com.hybris.cockpitng.core.persistence.impl.XMLWidgetPersistenceService.loadWidgetTree(XMLWidgetPersistenceService.java:84)

        at com.hybris.cockpitng.engine.impl.DefaultCockpitWidgetEngine.resolveWidgetInstance(DefaultCockpitWidgetEngine.java:212)

        at com.hybris.cockpitng.engine.impl.DefaultCockpitWidgetEngine.createWidgetView(DefaultCockpitWidgetEngine.java:150)

       at com.hybris.cockpitng.engine.impl.AdminmodeWidgetEngine.createWidgetView(AdminmodeWidgetEngine.java:95)

        at com.hybris.cockpitng.components.Widgetslot.updateView(Widgetslot.java:73)

After create new backoffic extension, and login to the http://localhost:9001/backoffice/. The above error occurred.

Run ant clean all again, it seems some of the newly generated code not being deployed to the server.