Stacktrace when adding an annotation

2012-04-19 16:55:10,586 [http://localhost:8080/xwiki/rest/wikis/xwiki/spaces/Main/pages/AnnotationsTest/annotations?media=json] WARN  c.x.x.o.BaseCollection         - Absolute XClass reference including a wiki reference (xwiki) used for an XObject class reference. The reference has been changed to relative. 
java.lang.Throwable: null
	at com.xpn.xwiki.objects.BaseCollection.setXClassReference(BaseCollection.java:208) [xwiki-platform-legacy-oldcore-4.0-20120419.105949-227.jar:na]
	at com.xpn.xwiki.objects.BaseObject.setXClassReference(BaseObject.java:113) [xwiki-platform-legacy-oldcore-4.0-20120419.105949-227.jar:na]
	at com.xpn.xwiki.doc.XWikiDocument.createXObject(XWikiDocument.java:2050) [xwiki-platform-legacy-oldcore-4.0-20120419.105949-227.jar:na]
	at org.xwiki.annotation.io.internal.DefaultIOService.addAnnotation(DefaultIOService.java:125) [xwiki-platform-annotation-io-4.0-20120419.095922-253.jar:na]
	at org.xwiki.annotation.internal.DefaultAnnotationService.addAnnotation(DefaultAnnotationService.java:103) [xwiki-platform-annotation-core-4.0-20120419.095710-256.jar:na]
	at org.xwiki.annotation.rest.internal.AnnotationsRESTResource.doPostAnnotation(AnnotationsRESTResource.java:171) [xwiki-platform-annotation-rest-4.0-20120419.095950-253.jar:na]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.6.0_22]
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) ~[na:1.6.0_22]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.6.0_22]
	at java.lang.reflect.Method.invoke(Method.java:616) ~[na:1.6.0_22]
	at org.restlet.ext.jaxrs.internal.wrappers.AbstractMethodWrapper.internalInvoke(AbstractMethodWrapper.java:171) [org.restlet.ext.jaxrs-2.0.13.jar:na]
	at org.restlet.ext.jaxrs.internal.wrappers.ResourceMethod.invoke(ResourceMethod.java:291) [org.restlet.ext.jaxrs-2.0.13.jar:na]
	at org.restlet.ext.jaxrs.JaxRsRestlet.invokeMethod(JaxRsRestlet.java:1043) [org.restlet.ext.jaxrs-2.0.13.jar:na]
	at org.restlet.ext.jaxrs.JaxRsRestlet.handle(JaxRsRestlet.java:792) [org.restlet.ext.jaxrs-2.0.13.jar:na]
	at org.restlet.routing.Filter.doHandle(Filter.java:159) [org.restlet-2.0.13.jar:na]
	at org.restlet.routing.Filter.handle(Filter.java:206) [org.restlet-2.0.13.jar:na]
	at org.restlet.routing.Router.doHandle(Router.java:500) [org.restlet-2.0.13.jar:na]
	at org.restlet.routing.Router.handle(Router.java:740) [org.restlet-2.0.13.jar:na]
	at org.restlet.routing.Filter.doHandle(Filter.java:159) [org.restlet-2.0.13.jar:na]
	at org.restlet.routing.Filter.handle(Filter.java:206) [org.restlet-2.0.13.jar:na]
	at org.restlet.routing.Filter.doHandle(Filter.java:159) [org.restlet-2.0.13.jar:na]
	at org.restlet.routing.Filter.handle(Filter.java:206) [org.restlet-2.0.13.jar:na]
	at org.restlet.routing.Filter.doHandle(Filter.java:159) [org.restlet-2.0.13.jar:na]
	at org.restlet.routing.Filter.handle(Filter.java:206) [org.restlet-2.0.13.jar:na]
	at org.restlet.routing.Filter.doHandle(Filter.java:159) [org.restlet-2.0.13.jar:na]
	at org.restlet.routing.Filter.handle(Filter.java:206) [org.restlet-2.0.13.jar:na]
	at org.restlet.routing.Filter.doHandle(Filter.java:159) [org.restlet-2.0.13.jar:na]
	at org.restlet.engine.application.StatusFilter.doHandle(StatusFilter.java:154) [org.restlet-2.0.13.jar:na]
	at org.restlet.routing.Filter.handle(Filter.java:206) [org.restlet-2.0.13.jar:na]
	at org.restlet.routing.Filter.doHandle(Filter.java:159) [org.restlet-2.0.13.jar:na]
	at org.restlet.routing.Filter.handle(Filter.java:206) [org.restlet-2.0.13.jar:na]
	at org.restlet.engine.ChainHelper.handle(ChainHelper.java:114) [org.restlet-2.0.13.jar:na]
	at org.restlet.engine.application.ApplicationHelper.handle(ApplicationHelper.java:75) [org.restlet-2.0.13.jar:na]
	at org.restlet.Application.handle(Application.java:391) [org.restlet-2.0.13.jar:na]
	at org.restlet.routing.Filter.doHandle(Filter.java:159) [org.restlet-2.0.13.jar:na]
	at org.restlet.routing.Filter.handle(Filter.java:206) [org.restlet-2.0.13.jar:na]
	at org.restlet.routing.Router.doHandle(Router.java:500) [org.restlet-2.0.13.jar:na]
	at org.restlet.routing.Router.handle(Router.java:740) [org.restlet-2.0.13.jar:na]
	at org.restlet.routing.Filter.doHandle(Filter.java:159) [org.restlet-2.0.13.jar:na]
	at org.restlet.routing.Filter.handle(Filter.java:206) [org.restlet-2.0.13.jar:na]
	at org.restlet.routing.Router.doHandle(Router.java:500) [org.restlet-2.0.13.jar:na]
	at org.restlet.routing.Router.handle(Router.java:740) [org.restlet-2.0.13.jar:na]
	at org.restlet.routing.Filter.doHandle(Filter.java:159) [org.restlet-2.0.13.jar:na]
	at org.restlet.routing.Filter.handle(Filter.java:206) [org.restlet-2.0.13.jar:na]
	at org.restlet.engine.ChainHelper.handle(ChainHelper.java:114) [org.restlet-2.0.13.jar:na]
	at org.restlet.Component.handle(Component.java:391) [org.restlet-2.0.13.jar:na]
	at org.restlet.Server.handle(Server.java:491) [org.restlet-2.0.13.jar:na]
	at org.restlet.engine.ServerHelper.handle(ServerHelper.java:74) [org.restlet-2.0.13.jar:na]
	at org.restlet.engine.http.HttpServerHelper.handle(HttpServerHelper.java:153) [org.restlet-2.0.13.jar:na]
	at org.restlet.ext.servlet.ServerServlet.service(ServerServlet.java:1031) [org.restlet.ext.servlet-2.0.13.jar:na]
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:820) [servlet-api-2.5.jar:2.5]
	at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:538) [jetty-servlet-7.4.5.v20110725.jar:7.4.5.v20110725]
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1352) [jetty-servlet-7.4.5.v20110725.jar:7.4.5.v20110725]
	at org.xwiki.wysiwyg.server.filter.XWikiContextInitializationFilter.doFilter(XWikiContextInitializationFilter.java:79) [xwiki-platform-wysiwyg-server-4.0-SNAPSHOT.jar:na]
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1323) [jetty-servlet-7.4.5.v20110725.jar:7.4.5.v20110725]
	at com.xpn.xwiki.plugin.webdav.XWikiDavFilter.doFilter(XWikiDavFilter.java:66) [xwiki-platform-webdav-server-4.0-20120419.095146-259.jar:na]
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1323) [jetty-servlet-7.4.5.v20110725.jar:7.4.5.v20110725]
	at org.xwiki.container.servlet.filters.internal.SavedRequestRestorerFilter.doFilter(SavedRequestRestorerFilter.java:208) [xwiki-platform-container-servlet-4.0-20120419.093835-268.jar:na]
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1323) [jetty-servlet-7.4.5.v20110725.jar:7.4.5.v20110725]
	at org.xwiki.container.servlet.filters.internal.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:111) [xwiki-platform-container-servlet-4.0-20120419.093835-268.jar:na]
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1323) [jetty-servlet-7.4.5.v20110725.jar:7.4.5.v20110725]
	at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:476) [jetty-servlet-7.4.5.v20110725.jar:7.4.5.v20110725]
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:119) [jetty-server-7.4.5.v20110725.jar:7.4.5.v20110725]
	at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:517) [jetty-security-7.4.5.v20110725.jar:7.4.5.v20110725]
	at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:225) [jetty-server-7.4.5.v20110725.jar:7.4.5.v20110725]
	at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:937) [jetty-server-7.4.5.v20110725.jar:7.4.5.v20110725]
	at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:406) [jetty-servlet-7.4.5.v20110725.jar:7.4.5.v20110725]
	at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:183) [jetty-server-7.4.5.v20110725.jar:7.4.5.v20110725]
	at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:871) [jetty-server-7.4.5.v20110725.jar:7.4.5.v20110725]
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:117) [jetty-server-7.4.5.v20110725.jar:7.4.5.v20110725]
	at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:247) [jetty-server-7.4.5.v20110725.jar:7.4.5.v20110725]
	at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:149) [jetty-server-7.4.5.v20110725.jar:7.4.5.v20110725]
	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:110) [jetty-server-7.4.5.v20110725.jar:7.4.5.v20110725]
	at org.eclipse.jetty.server.Server.handle(Server.java:346) [jetty-server-7.4.5.v20110725.jar:7.4.5.v20110725]
	at org.eclipse.jetty.server.HttpConnection.handleRequest(HttpConnection.java:589) [jetty-server-7.4.5.v20110725.jar:7.4.5.v20110725]
	at org.eclipse.jetty.server.HttpConnection$RequestHandler.content(HttpConnection.java:1065) [jetty-server-7.4.5.v20110725.jar:7.4.5.v20110725]
	at org.eclipse.jetty.http.HttpParser.parseNext(HttpParser.java:823) [jetty-http-7.4.5.v20110725.jar:7.4.5.v20110725]
	at org.eclipse.jetty.http.HttpParser.parseAvailable(HttpParser.java:220) [jetty-http-7.4.5.v20110725.jar:7.4.5.v20110725]
	at org.eclipse.jetty.server.HttpConnection.handle(HttpConnection.java:411) [jetty-server-7.4.5.v20110725.jar:7.4.5.v20110725]
	at org.eclipse.jetty.io.nio.SelectChannelEndPoint.handle(SelectChannelEndPoint.java:535) [jetty-io-7.4.5.v20110725.jar:7.4.5.v20110725]
	at org.eclipse.jetty.io.nio.SelectChannelEndPoint$1.run(SelectChannelEndPoint.java:40) [jetty-io-7.4.5.v20110725.jar:7.4.5.v20110725]
	at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:529) [jetty-util-7.4.5.v20110725.jar:7.4.5.v20110725]
	at java.lang.Thread.run(Thread.java:679) [na:1.6.0_22]