Yikes!

javax.el.ELException: Problems calling function [fn:length]
	at org.apache.el.parser.AstFunction.getValue(AstFunction.java:197)
	at org.apache.el.parser.AstGreaterThan.getValue(AstGreaterThan.java:36)
	at org.apache.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:189)
	at org.apache.jasper.runtime.PageContextImpl.proprietaryEvaluate(PageContextImpl.java:942)
	at org.apache.jsp.WEB_002dINF.pages.search.study.matrix_jsp._jspx_meth_c_005fif_005f2(matrix_jsp.java:851)
	at org.apache.jsp.WEB_002dINF.pages.search.study.matrix_jsp._jspx_meth_c_005fforEach_005f0(matrix_jsp.java:813)
	at org.apache.jsp.WEB_002dINF.pages.search.study.matrix_jsp._jspService(matrix_jsp.java:227)
	at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:583)
	at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:465)
	at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:383)
	at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:331)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:583)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:212)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:156)
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:181)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:156)
	at com.opensymphony.module.sitemesh.filter.PageFilter.doFilter(PageFilter.java:39)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:181)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:156)
	at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:662)
	at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:428)
	at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:360)
	at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:297)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at net.bull.javamelody.JspWrapper.invoke(JspWrapper.java:152)
	at net.bull.javamelody.JdbcWrapper$DelegatingInvocationHandler.invoke(JdbcWrapper.java:294)
	at com.sun.proxy.$Proxy159.forward(Unknown Source)
	at org.springframework.web.servlet.view.InternalResourceView.renderMergedOutputModel(InternalResourceView.java:142)
	at org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:239)
	at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1142)
	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:879)
	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:792)
	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:476)
	at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:431)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:489)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:583)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:212)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:156)
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:181)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:156)
	at net.bull.javamelody.MonitoringFilter.doFilter(MonitoringFilter.java:239)
	at net.bull.javamelody.MonitoringFilter.doFilter(MonitoringFilter.java:215)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:181)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:156)
	at org.tuckey.web.filters.urlrewrite.RuleChain.handleRewrite(RuleChain.java:164)
	at org.tuckey.web.filters.urlrewrite.RuleChain.doRules(RuleChain.java:141)
	at org.tuckey.web.filters.urlrewrite.UrlRewriter.processRequest(UrlRewriter.java:90)
	at org.tuckey.web.filters.urlrewrite.UrlRewriteFilter.doFilter(UrlRewriteFilter.java:406)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:181)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:156)
	at org.displaytag.filter.ResponseOverrideFilter.doFilter(ResponseOverrideFilter.java:125)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:181)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:156)
	at org.springframework.orm.hibernate3.support.OpenSessionInViewFilter.doFilterInternal(OpenSessionInViewFilter.java:198)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:75)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:181)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:156)
	at com.opensymphony.module.sitemesh.filter.PageFilter.parsePage(PageFilter.java:119)
	at com.opensymphony.module.sitemesh.filter.PageFilter.doFilter(PageFilter.java:55)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:181)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:156)
	at org.acegisecurity.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:264)
	at org.acegisecurity.intercept.web.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:107)
	at org.acegisecurity.intercept.web.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:72)
	at org.acegisecurity.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:274)
	at org.acegisecurity.ui.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:110)
	at org.acegisecurity.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:274)
	at org.acegisecurity.wrapper.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:81)
	at org.acegisecurity.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:274)
	at org.acegisecurity.ui.AbstractProcessingFilter.doFilter(AbstractProcessingFilter.java:217)
	at org.acegisecurity.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:274)
	at org.acegisecurity.context.HttpSessionContextIntegrationFilter.doFilter(HttpSessionContextIntegrationFilter.java:191)
	at org.acegisecurity.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:274)
	at org.acegisecurity.util.FilterChainProxy.doFilter(FilterChainProxy.java:148)
	at org.acegisecurity.util.FilterToBeanProxy.doFilter(FilterToBeanProxy.java:90)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:181)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:156)
	at net.bull.javamelody.MonitoringFilter.doFilter(MonitoringFilter.java:199)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:181)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:156)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:168)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:90)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:483)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:130)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:93)
	at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:679)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:346)
	at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:617)
	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:63)
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:934)
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1690)
	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:52)
	at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191)
	at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659)
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:63)
	at java.lang.Thread.run(Thread.java:750)
Caused by: org.hibernate.SessionException: Session is closed!
	at org.hibernate.impl.AbstractSessionImpl.errorIfClosed(AbstractSessionImpl.java:49)
	at org.hibernate.impl.SessionImpl.getPersistenceContext(SessionImpl.java:1823)
	at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:232)
	at org.hibernate.loader.Loader.loadCollectionBatch(Loader.java:2032)
	at org.hibernate.loader.collection.BatchingCollectionInitializer.initialize(BatchingCollectionInitializer.java:47)
	at org.hibernate.persister.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:565)
	at org.hibernate.event.def.DefaultInitializeCollectionEventListener.onInitializeCollection(DefaultInitializeCollectionEventListener.java:63)
	at org.hibernate.impl.SessionImpl.initializeCollection(SessionImpl.java:1716)
	at org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:344)
	at org.hibernate.collection.AbstractPersistentCollection.read(AbstractPersistentCollection.java:86)
	at org.hibernate.collection.AbstractPersistentCollection.readSize(AbstractPersistentCollection.java:109)
	at org.hibernate.collection.PersistentSet.size(PersistentSet.java:139)
	at java.util.Collections$UnmodifiableCollection.size(Collections.java:1032)
	at org.apache.taglibs.standard.functions.Functions.length(Functions.java:193)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.apache.el.parser.AstFunction.getValue(AstFunction.java:186)
	... 102 more