Simultaneous logins can lead to ConcurrentModificationExceptions with the EventLogger

java.util.ConcurrentModificationException
at java.util.HashMap$HashIterator.nextEntry(HashMap.java:841)
at java.util.HashMap$ValueIterator.next(HashMap.java:871)
at java.util.Collections$UnmodifiableCollection$1.next(Collections.java:1010)
at org.apache.jackrabbit.core.state.SessionItemStateManager.getDescendantTransientItemStates(SessionItemStateManager.java:394)
at org.apache.jackrabbit.core.ItemImpl.getTransientStates(ItemImpl.java:362)
at org.apache.jackrabbit.core.ItemImpl.save(ItemImpl.java:1083)
at org.hippoecm.repository.EventLogger.logEvent(EventLogger.java:139)
at org.hippoecm.repository.jackrabbit.RepositoryImpl.login(RepositoryImpl.java:191)
at org.hippoecm.repository.decorating.RepositoryDecorator.login(RepositoryDecorator.java:73)
at org.hippoecm.repository.HippoRepositoryImpl.login(HippoRepositoryImpl.java:111)
at org.hippoecm.repository.HippoRepositoryImpl.login(HippoRepositoryImpl.java:99)
at org.hippoecm.repository.RepositoryServlet.doGet(RepositoryServlet.java:254)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:707)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:487)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1093)
at org.apache.wicket.protocol.http.WicketFilter.doFilter(WicketFilter.java:246)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1084)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:360)
at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:181)
at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:726)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:405)
at org.mortbay.jetty.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:206)
at org.mortbay.jetty.handler.HandlerCollection.handle(HandlerCollection.java:114)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at org.mortbay.jetty.Server.handle(Server.java:324)
at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:505)
at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:829)
at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:514)
at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:211)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:380)
at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:395)
at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:488)