RS concurrent delete / close course

2016-02-18 12:00:56,278 [ajp-nio2-8021-exec-29] ERROR OLATRuntimeException - OLAT::ERROR ^%^ N1-E43

https://xyz.de/auth/RepositorySite/0/My/0 ^%^ Mozilla/5.0 (Windows NT 6.1; rv:44.0) Gecko/20100101 Firefox/44.0 ^%^ **RedScreen**

<dispatchinfo>
	<componentinfo>
		<compname>c3</compname>
		<compclass>org.olat.core.gui.components.link.Link</compclass>
		<extendedinfo>n/a</extendedinfo>
		<event>
			<class&gt;org.olat.core.gui.control.Event</class&gt;
			<command>c3</command>
			<tostring>com:c3,org.olat.core.gui.control.Event@c4f</tostring>
		</event>
	</componentinfo>
	<controllerinfo>
		<controllername>org.olat.core.commons.fullWebApp.BaseFullWebappController</controllername>
	</controllerinfo>
</dispatchinfo>

>>> stack of 1.cause::org.olat.core.logging.OLATRuntimeException: null
-> at org.olat.core.gui.exception.ExceptionWindowController.<init>(ExceptionWindowController.java:116)
   at org.olat.core.gui.exception.MsgFactory.createMessageChiefController(MsgFactory.java:57)
   at org.olat.core.gui.exception.MsgFactory.createMessageChiefController(MsgFactory.java:46)
   at org.olat.core.gui.components.Window.dispatchRequest(Window.java:536)
   at org.olat.core.gui.components.Window.doDispatchRequest(Window.java:234)
   at org.olat.core.gui.components.AbstractComponent.dispatchRequest(AbstractComponent.java:193)
   at org.olat.dispatcher.AuthenticatedDispatcher.processValidDispatchURI(AuthenticatedDispatcher.java:298)
   at org.olat.dispatcher.AuthenticatedDispatcher.execute(AuthenticatedDispatcher.java:216)
   at org.olat.core.servlets.OpenOLATServlet.executeUserRequest(OpenOLATServlet.java:289)
   at org.olat.core.servlets.OpenOLATServlet.doPost(OpenOLATServlet.java:232)
   at javax.servlet.http.HttpServlet.service(HttpServlet.java:648)
>>> stack of 2.cause::java.lang.NullPointerException: null
-> at org.olat.course.PersistingCourseImpl.<init>(PersistingCourseImpl.java:128)
   at org.olat.course.CourseFactory.loadCourse(CourseFactory.java:289)
   at org.olat.course.editor.EditorMainController.requestForClose(EditorMainController.java:355)
   at org.olat.course.run.CourseRuntimeController.requestForClose(CourseRuntimeController.java:689)
   at org.olat.core.commons.fullWebApp.BaseFullWebappController.requestCloseTab(BaseFullWebappController.java:1043)
   at org.olat.core.commons.fullWebApp.BaseFullWebappController.event(BaseFullWebappController.java:622)
   at org.olat.core.gui.control.DefaultController.dispatchEvent(DefaultController.java:202)
   at org.olat.core.gui.components.AbstractComponent$1.run(AbstractComponent.java:240)
   at org.olat.core.logging.activity.ThreadLocalUserActivityLoggerInstaller.runWithUserActivityLogger(ThreadLocalUserActivityLoggerInstaller.java:108)
   at org.olat.core.gui.components.AbstractComponent.fireEvent(AbstractComponent.java:238)
   at org.olat.core.gui.components.link.Link.dispatch(Link.java:198)