Every time i have to restart tomcat to make links to work on my pages. After i restart , after couple of hours again they are broken. Is it tomcat server issue or my spring security issue?

Please help...

HTTP Status 500 -
type Exception report
message
description The server encountered an internal error () that prevented it from fulfilling this request.
exception
org.apache.jasper.JasperException: tag 'select', field 'list', name 'student.branchId': The requested list key 'branchDetails' could not be resolved as a collection/array/map/enumeration/iterator type. Example: people or people.{name}
org.apache.jasper.servlet.JspServletWrapper.handle JspException(JspServletWrapper.java:500)
org.apache.jasper.servlet.JspServletWrapper.servic e(JspServletWrapper.java:413)
org.apache.jasper.servlet.JspServlet.serviceJspFil e(JspServlet.java:308)
org.apache.jasper.servlet.JspServlet.service(JspSe rvlet.java:259)
javax.servlet.http.HttpServlet.service(HttpServlet .java:729)
org.springframework.security.web.FilterChainProxy$ VirtualFilterChain.doFilter(FilterChainProxy.java: 312)
org.springframework.security.web.access.intercept. FilterSecurityInterceptor.invoke(FilterSecurityInt erceptor.java:107)
org.springframework.security.web.access.intercept. FilterSecurityInterceptor.doFilter(FilterSecurityI nterceptor.java:83)
org.springframework.security.web.FilterChainProxy$ VirtualFilterChain.doFilter(FilterChainProxy.java: 324)
org.springframework.security.web.access.ExceptionT ranslationFilter.doFilter(ExceptionTranslationFilt er.java:95)
org.springframework.security.web.FilterChainProxy$ VirtualFilterChain.doFilter(FilterChainProxy.java: 324)
org.springframework.security.web.session.SessionMa nagementFilter.doFilter(SessionManagementFilter.ja va:60)
org.springframework.security.web.FilterChainProxy$ VirtualFilterChain.doFilter(FilterChainProxy.java: 324)
org.springframework.security.web.authentication.An onymousAuthenticationFilter.doFilter(AnonymousAuth enticationFilter.java:79)
org.springframework.security.web.FilterChainProxy$ VirtualFilterChain.doFilter(FilterChainProxy.java: 324)
org.springframework.security.web.servletapi.Securi tyContextHolderAwareRequestFilter.doFilter(Securit yContextHolderAwareRequestFilter.java:54)
org.springframework.security.web.FilterChainProxy$ VirtualFilterChain.doFilter(FilterChainProxy.java: 324)
org.springframework.security.web.savedrequest.Requ estCacheAwareFilter.doFilter(RequestCacheAwareFilt er.java:35)
org.springframework.security.web.FilterChainProxy$ VirtualFilterChain.doFilter(FilterChainProxy.java: 324)
org.springframework.security.web.authentication.ui .DefaultLoginPageGeneratingFilter.doFilter(Default LoginPageGeneratingFilter.java:91)
org.springframework.security.web.FilterChainProxy$ VirtualFilterChain.doFilter(FilterChainProxy.java: 324)
org.springframework.security.web.authentication.Ab stractAuthenticationProcessingFilter.doFilter(Abst ractAuthenticationProcessingFilter.java:187)
org.springframework.security.web.FilterChainProxy$ VirtualFilterChain.doFilter(FilterChainProxy.java: 324)
org.springframework.security.web.authentication.lo gout.LogoutFilter.doFilter(LogoutFilter.java:105)
org.springframework.security.web.FilterChainProxy$ VirtualFilterChain.doFilter(FilterChainProxy.java: 324)
org.springframework.security.web.context.SecurityC ontextPersistenceFilter.doFilter(SecurityContextPe rsistenceFilter.java:58)
org.springframework.security.web.FilterChainProxy$ VirtualFilterChain.doFilter(FilterChainProxy.java: 324)
org.springframework.security.web.session.Concurren tSessionFilter.doFilter(ConcurrentSessionFilter.ja va:109)
org.springframework.security.web.FilterChainProxy$ VirtualFilterChain.doFilter(FilterChainProxy.java: 324)
org.springframework.security.web.FilterChainProxy. doFilter(FilterChainProxy.java:165)
org.springframework.web.filter.DelegatingFilterPro xy.invokeDelegate(DelegatingFilterProxy.java:237)
org.springframework.web.filter.DelegatingFilterPro xy.doFilter(DelegatingFilterProxy.java:167)
org.apache.struts2.dispatcher.ServletDispatcherRes ult.doExecute(ServletDispatcherResult.java:157)
org.apache.struts2.dispatcher.StrutsResultSupport. execute(StrutsResultSupport.java:186)
com.opensymphony.xwork2.DefaultActionInvocation.ex ecuteResult(DefaultActionInvocation.java:373)
com.opensymphony.xwork2.DefaultActionInvocation.in voke(DefaultActionInvocation.java:277)

org.apache.struts2.dispatcher.ng.filter.StrutsPrep areAndExecuteFilter.doFilter(StrutsPrepareAndExecu teFilter.java:91)
com.opensymphony.sitemesh.webapp.SiteMeshFilter.ob tainContent(SiteMeshFilter.java:129)
com.opensymphony.sitemesh.webapp.SiteMeshFilter.do Filter(SiteMeshFilter.java:77)
org.springframework.security.web.FilterChainProxy$ VirtualFilterChain.doFilter(FilterChainProxy.java: 312)


root cause

tag 'select', field 'list', name 'student.branchId': The requested list key 'branchDetails' could not be resolved as a collection/array/map/enumeration/iterator type. Example: people or people.{name} - [unknown location]
org.apache.struts2.components.Component.fieldError (Component.java:237)
org.apache.struts2.components.Component.findValue( Component.java:358)
org.apache.struts2.components.ListUIBean.evaluateE xtraParams(ListUIBean.java:80)
org.apache.struts2.components.Select.evaluateExtra Params(Select.java:105)
org.apache.struts2.components.UIBean.evaluateParam s(UIBean.java:856)
org.apache.struts2.components.UIBean.end(UIBean.ja va:510)
org.apache.struts2.views.jsp.ComponentTagSupport.d oEndTag(ComponentTagSupport.java:42)
org.apache.jsp.dpps.NewStudentInfo_jsp._jspx_meth_ s_005fselect_005f0(NewStudentInfo_jsp.java:682)
org.apache.jsp.dpps.NewStudentInfo_jsp._jspx_meth_ s_005fform_005f0(NewStudentInfo_jsp.java:209)
org.apache.jsp.dpps.NewStudentInfo_jsp._jspService (NewStudentInfo_jsp.java:100)
org.apache.jasper.runtime.HttpJspBase.service(Http JspBase.java:98)
javax.servlet.http.HttpServlet.service(HttpServlet .java:729)
org.apache.jasper.servlet.JspServletWrapper.servic e(JspServletWrapper.java:371)
org.apache.jasper.servlet.JspServlet.serviceJspFil e(JspServlet.java:308)
org.apache.jasper.servlet.JspServlet.service(JspSe rvlet.java:259)
javax.servlet.http.HttpServlet.service(HttpServlet .java:729)
org.springframework.security.web.FilterChainProxy$ VirtualFilterChain.doFilter(FilterChainProxy.java: 312)
org.springframework.security.web.access.intercept. FilterSecurityInterceptor.invoke(FilterSecurityInt erceptor.java:107)
org.springframework.security.web.access.intercept. FilterSecurityInterceptor.doFilter(FilterSecurityI nterceptor.java:8 work.web.filter.DelegatingFilterProxy.doFilter(Del egatingFil