The following exception is thrown when there are many server initiated updates occurring at the same time from different portlets:

2008-06-15 16:54:48,707 ERROR
[org.apache.catalina.core.ContainerBase.[jboss.web].[localhost].[/slp-gqast1.com-web].[Persistent
Faces Servlet]] Servlet.service() for servlet Persi
stent Faces Servlet threw exception
java.util.ConcurrentModificationException
        at java.util.HashMap$HashIterator.nextEntry(HashMap.java:841)
        at java.util.HashMap$EntryIterator.next(HashMap.java:883)
        at java.util.HashMap$EntryIterator.next(HashMap.java:881)
        at
com.icesoft.faces.context.BridgeExternalContext.collectBundles(BridgeExternalContext.java:207)
        at com.icesoft.faces.context.View.switchToPushMode(View.java:142)
        at
com.icesoft.faces.webapp.http.core.MultiViewServer.service(MultiViewServer.java:57)
        at
com.icesoft.faces.webapp.http.common.standard.PathDispatcherServer$Matcher.serviceOnMatch(PathDispatcherServer.java:50)
        at
com.icesoft.faces.webapp.http.common.standard.PathDispatcherServer.service(PathDispatcherServer.java:19)
        at
com.icesoft.faces.webapp.http.servlet.ThreadBlockingAdaptingServlet.service(ThreadBlockingAdaptingServlet.java:19)
        at
com.icesoft.faces.webapp.http.servlet.EnvironmentAdaptingServlet.service(EnvironmentAdaptingServlet.java:29)
        at
com.icesoft.faces.webapp.http.servlet.MainSessionBoundServlet.service(MainSessionBoundServlet.java:139)
        at
com.icesoft.faces.webapp.http.servlet.SessionDispatcher.service(SessionDispatcher.java:35)
        at
com.icesoft.faces.webapp.http.servlet.PathDispatcher$Matcher.serviceOnMatch(PathDispatcher.java:52)
        at
com.icesoft.faces.webapp.http.servlet.PathDispatcher.service(PathDispatcher.java:29)
        at
com.icesoft.faces.webapp.http.servlet.MainServlet.service(MainServlet.java:79)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
        at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
        at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at
org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:654)
        at
org.apache.catalina.core.ApplicationDispatcher.doInclude(ApplicationDispatcher.java:557)
        at
org.apache.catalina.core.ApplicationDispatcher.include(ApplicationDispatcher.java:481)
        at
com.liferay.portlet.PortletRequestDispatcherImpl.include(PortletRequestDispatcherImpl.java:245)
        at
com.liferay.portlet.PortletRequestDispatcherImpl.include(PortletRequestDispatcherImpl.java:87)
        at
com.icesoft.faces.webapp.http.portlet.MainPortlet.doInclude(MainPortlet.java:122)
        at
com.icesoft.faces.webapp.http.portlet.MainPortlet.doView(MainPortlet.java:55)
        at javax.portlet.GenericPortlet.doDispatch(GenericPortlet.java:235)
        at javax.portlet.GenericPortlet.render(GenericPortlet.java:163)
        at
com.liferay.portal.kernel.servlet.PortletServlet.service(PortletServlet.java:102)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
        at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
        at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at
org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:654)
        at
org.apache.catalina.core.ApplicationDispatcher.doInclude(ApplicationDispatcher.java:557)
        at
org.apache.catalina.core.ApplicationDispatcher.include(ApplicationDispatcher.java:481)
        at com.liferay.portlet.CachePortlet._invoke(CachePortlet.java:408)
        at com.liferay.portlet.CachePortlet.render(CachePortlet.java:251)
        at
org.apache.jsp.html.portal.render_005fportlet_jsp._jspService(render_005fportlet_jsp.java:1345)
        at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
        at
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:373)
        at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:336)
        at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)