It seems that URL.end will *some* times call PortletActionContext.isPortletRequest() to check if the current request is a portlet request. This will fail with a "java.lang.NoClassDefFoundError: javax/portlet/PortletRequest" if the portlet api is not present on the classpath.

The really insiduous thing about this bug is that the decision to check for portlet requests seems to be inconsistent. On rapidly reloading the same page, on the 150th load or so the problem appeared and persisted until I restarted tomcat. This means that the problem could go undetected during development and appear in deployment. Egg will be deposited on face.

I would suggest that:
  1) the consistency of whether to make this check be examined, and
  2) the PortletActionContext run a static initializer to verify that the javax.portlet.PorletRequest class is available and if not, simply always returns false from this and any similar methods.

Stack-trace:
2006-06-27 09:53:59,106 ERROR [org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:704)] Servlet.service() for servlet jsp threw exception
java.lang.NoClassDefFoundError: javax/portlet/PortletRequest
        at com.opensymphony.webwork.portlet.context.PortletActionContext.getRequest(PortletActionContext.java:70)
        at com.opensymphony.webwork.portlet.context.PortletActionContext.isPortletRequest(PortletActionContext.java:94)
        at com.opensymphony.webwork.components.URL.end(URL.java:180)
        at com.opensymphony.webwork.views.jsp.ComponentTagSupport.doEndTag(ComponentTagSupport.java:21)
        at org.apache.jsp.eplica.waf.admin.timerStatistics_jsp._jspx_meth_ww_url_0(org.apache.jsp.eplica.waf.admin.timerStatistics_jsp:777)
        at org.apache.jsp.eplica.waf.admin.timerStatistics_jsp._jspx_meth_ww_iterator_1(org.apache.jsp.eplica.waf.admin.timerStatistics_jsp:716)
        at org.apache.jsp.eplica.waf.admin.timerStatistics_jsp._jspx_meth_ww_if_1(org.apache.jsp.eplica.waf.admin.timerStatistics_jsp:658)
        at org.apache.jsp.eplica.waf.admin.timerStatistics_jsp._jspService(org.apache.jsp.eplica.waf.admin.timerStatistics_jsp:178)
        at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
        at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:332)
        at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
        at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
        at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:672)
        at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:463)
        at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:398)
        at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:301)
        at com.opensymphony.webwork.dispatcher.ServletDispatcherResult.doExecute(ServletDispatcherResult.java:114)
        at com.opensymphony.webwork.dispatcher.WebWorkResultSupport.execute(WebWorkResultSupport.java:101)
        at com.opensymphony.xwork.DefaultActionInvocation.executeResult(DefaultActionInvocation.java:312)
        at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:207)
        at com.eplica.waf.security.AuthorizationInterceptor$1.invoke(AuthorizationInterceptor.java:82)
        at com.eplica.waf.security.AuthorizationInterceptor.intercept(AuthorizationInterceptor.java:107)
        at com.eplica.waf.security.AuthorizationInterceptor.intercept(AuthorizationInterceptor.java:86)
        at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:189)
        at com.eplica.waf.utils.TransactionInterceptor.intercept(TransactionInterceptor.java:52)
        at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:189)
        at com.opensymphony.xwork.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:137)
        at com.opensymphony.xwork.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:81)
        at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:189)
        at com.opensymphony.xwork.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:115)
        at com.opensymphony.xwork.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:81)
        at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:189)
        at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:31)
        at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:189)
        at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:31)
        at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:189)
        at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:31)
        at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:189)
        at com.opensymphony.webwork.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:136)
        at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:189)
        at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:31)
        at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:189)
        at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:31)
        at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:189)
        at com.opensymphony.xwork.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:151)
        at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:189)
        at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:31)
        at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:189)
        at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:31)
        at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:189)
        at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:31)
        at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:189)
        at com.opensymphony.xwork.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:100)
        at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:189)
        at com.eplica.waf.utils.TimerInterceptor.intercept(TimerInterceptor.java:47)
        at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:189)
        at com.opensymphony.xwork.DefaultActionProxy.execute(DefaultActionProxy.java:113)
        at com.opensymphony.webwork.dispatcher.DispatcherUtils.serviceAction(DispatcherUtils.java:202)
        at com.opensymphony.webwork.dispatcher.FilterDispatcher.doFilter(FilterDispatcher.java:184)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
        at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
        at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:178)
        at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:432)
        at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:126)
        at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105)
        at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:107)
        at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148)
        at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:869)
        at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:667)
        at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527)
        at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:80)
        at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:684)
        at java.lang.Thread.run(Thread.java:595)