You stick to your code. However, update your code part such that when
create your ArrayList, do it as Collections.synchronizedList(new
ArrayList(...)).
Also, you must be removing or updating object directly inside your list
object which is why you're getting this error. Try to get a reference to
Iterator from your ArrayList object and invoke "remove" or "add" methods via
the Iterator to get away from the ConcurrentModificationException.
HTH
Eduardo
On Wed, Feb 27, 2008 at 5:48 AM, Othon Reyes Sanchez <[EMAIL PROTECTED]>
wrote:
> do you know a collection that is thread safe?
>
>
> On Tue, Feb 26, 2008 at 12:42 PM, Randy Burgess <[EMAIL PROTECTED]>
> wrote:
>
> > I believe this exception occurs when you try and modify an ArrayList
> while
> > iterating over said list. ArrayList is not thread safe.
> >
> > Regards,
> > Randy Burgess
> > Sr. Web Applications Developer
> > Nuvox Communications
> >
> >
> >
> > > From: Othon Reyes Sanchez <[EMAIL PROTECTED]>
> > > Reply-To: Struts Users Mailing List <user@struts.apache.org>
> > > Date: Tue, 26 Feb 2008 12:39:40 -0600
> > > To: <user@struts.apache.org>
> > > Subject: java.util.ConcurrentModificationException at
> IteratorComponent
> > >
> > > I get the following exception when i do some stress test with jmeter.
> > >> java.util.ConcurrentModificationException
> > >> at java.util.AbstractList$Itr.checkForComodification(Unknown
> > Source)
> > >> at java.util.AbstractList$Itr.next(Unknown Source)
> > >> at org.apache.struts2.components.IteratorComponent.end(
> > > IteratorComponent.java:246)
> > >> at org.apache.struts2.views.jsp.IteratorTag.doAfterBody(
> > > IteratorTag.java:68)
> > >> at
> > >
> >
> org.apache.jsp.jupiters2.archivo.jsp.expediente.frmPrestamo_jsp._jspx_meth_s_0
> > > 05fiterator_005f0
> > > (frmPrestamo_jsp.java:1595)
> > >> at
> > >
> >
> org.apache.jsp.jupiters2.archivo.jsp.expediente.frmPrestamo_jsp._jspx_meth_s_0
> > > 05fform_005f0
> > > (frmPrestamo_jsp.java:640)
> > >> at
> > >
> >
> org.apache.jsp.jupiters2.archivo.jsp.expediente.frmPrestamo_jsp._jspService
> > > (frmPrestamo_jsp.java:186)
> > >> at org.apache.jasper.runtime.HttpJspBase.service(
> HttpJspBase.java
> > > :98)
> > >> at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
> > >> at org.apache.jasper.servlet.JspServletWrapper.service(
> > > JspServletWrapper.java:328)
> > >> at org.apache.jasper.servlet.JspServlet.serviceJspFile(
> > > JspServlet.java:315)
> > >> at org.apache.jasper.servlet.JspServlet.service(JspServlet.java
> > :265)
> > >> at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
> > >> at
> > org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(
> > > ApplicationFilterChain.java:269)
> > >> at org.apache.catalina.core.ApplicationFilterChain.doFilter(
> > > ApplicationFilterChain.java:188)
> > >> at org.apache.catalina.core.ApplicationDispatcher.invoke(
> > > ApplicationDispatcher.java:691)
> > >> at
> org.apache.catalina.core.ApplicationDispatcher.processRequest(
> > > ApplicationDispatcher.java:469)
> > >> at org.apache.catalina.core.ApplicationDispatcher.doForward(
> > > ApplicationDispatcher.java:403)
> > >> at org.apache.catalina.core.ApplicationDispatcher.forward(
> > > ApplicationDispatcher.java:301)
> > >> at
> > org.apache.struts2.dispatcher.ServletDispatcherResult.doExecute(
> > > ServletDispatcherResult.java:139)
> > >> at org.apache.struts2.dispatcher.StrutsResultSupport.execute(
> > > StrutsResultSupport.java:178)
> > >> at
> com.opensymphony.xwork2.DefaultActionInvocation.executeResult(
> > > DefaultActionInvocation.java:348)
> > >> at com.opensymphony.xwork2.DefaultActionInvocation.invoke(
> > > DefaultActionInvocation.java:253)
> > >> at
> > >
> >
> com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept
> > (
> > > DefaultWorkflowInterceptor.java:221)
> > >> at
> > > com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(
> > > MethodFilterInterceptor.java:86)
> > >> at
> com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(
> > > DefaultActionInvocation.java:224)
> > >> at
> com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(
> > > DefaultActionInvocation.java:223)
> > >> at
> com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(
> > > UtilTimerStack.java:455)
> > >> at com.opensymphony.xwork2.DefaultActionInvocation.invoke(
> > > DefaultActionInvocation.java:221)
> > >> at
> > > com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(
> > > ValidationInterceptor.java:150)
> > >> at
> > >
> >
> org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIn
> > > tercept
> > > (AnnotationValidationInterceptor.java:48)
> > >> at
> > > com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(
> > > MethodFilterInterceptor.java:86)
> > >> at
> com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(
> > > DefaultActionInvocation.java:224)
> > >> at
> com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(
> > > DefaultActionInvocation.java:223)
> > >> at
> com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(
> > > UtilTimerStack.java:455)
> > >> at com.opensymphony.xwork2.DefaultActionInvocation.invoke(
> > > DefaultActionInvocation.java:221)
> > >> at
> > >
> com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept
> > (
> > > ConversionErrorInterceptor.java:123)
> > >> at
> com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(
> > > DefaultActionInvocation.java:224)
> > >> at
> com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(
> > > DefaultActionInvocation.java:223)
> > >> at
> com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(
> > > UtilTimerStack.java:455)
> > >> at com.opensymphony.xwork2.DefaultActionInvocation.invoke(
> > > DefaultActionInvocation.java:221)
> > >> at
> > > com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(
> > > ParametersInterceptor.java:167)
> > >> at
> > > com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(
> > > MethodFilterInterceptor.java:86)
> > >> at
> com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(
> > > DefaultActionInvocation.java:224)
> > >> at
> com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(
> > > DefaultActionInvocation.java:223)
> > >> at
> com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(
> > > UtilTimerStack.java:455)
> > >> at com.opensymphony.xwork2.DefaultActionInvocation.invoke(
> > > DefaultActionInvocation.java:221)
> > >> at
> > >
> >
> com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(
> > > StaticParametersInterceptor.java:105)
> > >> at
> com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(
> > > DefaultActionInvocation.java:224)
> > >> at
> com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(
> > > DefaultActionInvocation.java:223)
> > >> at
> com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(
> > > UtilTimerStack.java:455)
> > >> at com.opensymphony.xwork2.DefaultActionInvocation.invoke(
> > > DefaultActionInvocation.java:221)
> > >> at org.apache.struts2.interceptor.CheckboxInterceptor.intercept
> (
> > > CheckboxInterceptor.java:83)
> > >> at
> com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(
> > > DefaultActionInvocation.java:224)
> > >> at
> com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(
> > > DefaultActionInvocation.java:223)
> > >> at
> com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(
> > > UtilTimerStack.java:455)
> > >> at com.opensymphony.xwork2.DefaultActionInvocation.invoke(
> > > DefaultActionInvocation.java:221)
> > >> at
> org.apache.struts2.interceptor.FileUploadInterceptor.intercept
> > (
> > > FileUploadInterceptor.java:207)
> > >> at
> com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(
> > > DefaultActionInvocation.java:224)
> > >> at
> com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(
> > > DefaultActionInvocation.java:223)
> > >> at
> com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(
> > > UtilTimerStack.java:455)
> > >> at com.opensymphony.xwork2.DefaultActionInvocation.invoke(
> > > DefaultActionInvocation.java:221)
> > >> at
> > > com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(
> > > ModelDrivenInterceptor.java:74)
> > >> at
> com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(
> > > DefaultActionInvocation.java:224)
> > >> at
> com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(
> > > DefaultActionInvocation.java:223)
> > >> at
> com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(
> > > UtilTimerStack.java:455)
> > >> at com.opensymphony.xwork2.DefaultActionInvocation.invoke(
> > > DefaultActionInvocation.java:221)
> > >> at
> > >
> >
> com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept
> > (
> > > ScopedModelDrivenInterceptor.java:127)
> > >> at
> com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(
> > > DefaultActionInvocation.java:224)
> > >> at
> com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(
> > > DefaultActionInvocation.java:223)
> > >> at
> com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(
> > > UtilTimerStack.java:455)
> > >> at com.opensymphony.xwork2.DefaultActionInvocation.invoke(
> > > DefaultActionInvocation.java:221)
> > >> at
> > >
> org.apache.struts2.interceptor.ProfilingActivationInterceptor.intercept(
> > > ProfilingActivationInterceptor.java:107)
> > >> at
> com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(
> > > DefaultActionInvocation.java:224)
> > >> at
> com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(
> > > DefaultActionInvocation.java:223)
> > >> at
> com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(
> > > UtilTimerStack.java:455)
> > >> at com.opensymphony.xwork2.DefaultActionInvocation.invoke(
> > > DefaultActionInvocation.java:221)
> > >> at
> > >
> org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(
> > > DebuggingInterceptor.java:206)
> > >> at
> com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(
> > > DefaultActionInvocation.java:224)
> > >> at
> com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(
> > > DefaultActionInvocation.java:223)
> > >> at
> com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(
> > > UtilTimerStack.java:455)
> > >> at com.opensymphony.xwork2.DefaultActionInvocation.invoke(
> > > DefaultActionInvocation.java:221)
> > >> at
> > com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept
> > > (ChainingInterceptor.java:115)
> > >> at
> com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(
> > > DefaultActionInvocation.java:224)
> > >> at
> com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(
> > > DefaultActionInvocation.java:223)
> > >> at
> com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(
> > > UtilTimerStack.java:455)
> > >> at com.opensymphony.xwork2.DefaultActionInvocation.invoke(
> > > DefaultActionInvocation.java:221)
> > >> at
> com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept(
> > > I18nInterceptor.java:143)
> > >> at
> com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(
> > > DefaultActionInvocation.java:224)
> > >> at
> com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(
> > > DefaultActionInvocation.java:223)
> > >> at
> com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(
> > > UtilTimerStack.java:455)
> > >> at com.opensymphony.xwork2.DefaultActionInvocation.invoke(
> > > DefaultActionInvocation.java:221)
> > >> at
> > > com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(
> > > PrepareInterceptor.java:121)
> > >> at
> > > com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(
> > > MethodFilterInterceptor.java:86)
> > >> at
> com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(
> > > DefaultActionInvocation.java:224)
> > >> at
> com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(
> > > DefaultActionInvocation.java:223)
> > >> at
> com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(
> > > UtilTimerStack.java:455)
> > >> at com.opensymphony.xwork2.DefaultActionInvocation.invoke(
> > > DefaultActionInvocation.java:221)
> > >> at
> > org.apache.struts2.interceptor.ServletConfigInterceptor.intercept
> > > (ServletConfigInterceptor.java:170)
> > >> at
> com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(
> > > DefaultActionInvocation.java:224)
> > >> at
> com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(
> > > DefaultActionInvocation.java:223)
> > >> at
> com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(
> > > UtilTimerStack.java:455)
> > >> at com.opensymphony.xwork2.DefaultActionInvocation.invoke(
> > > DefaultActionInvocation.java:221)
> > >> at
> com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept
> > (
> > > AliasInterceptor.java:123)
> > >> at
> com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(
> > > DefaultActionInvocation.java:224)
> > >> at
> com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(
> > > DefaultActionInvocation.java:223)
> > >> at
> com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(
> > > UtilTimerStack.java:455)
> > >> at com.opensymphony.xwork2.DefaultActionInvocation.invoke(
> > > DefaultActionInvocation.java:221)
> > >> at
> > >
> >
> com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(
> > > ExceptionMappingInterceptor.java:176)
> > >> at
> com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(
> > > DefaultActionInvocation.java:224)
> > >> at
> com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(
> > > DefaultActionInvocation.java:223)
> > >> at
> com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(
> > > UtilTimerStack.java:455)
> > >> at com.opensymphony.xwork2.DefaultActionInvocation.invoke(
> > > DefaultActionInvocation.java:221)
> > >> at org.apache.struts2.impl.StrutsActionProxy.execute(
> > > StrutsActionProxy.java:50)
> > >> at org.apache.struts2.dispatcher.Dispatcher.serviceAction(
> > > Dispatcher.java:504)
> > >> at org.apache.struts2.dispatcher.FilterDispatcher.doFilter(
> > > FilterDispatcher.java:419)
> > >> at
> > org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(
> > > ApplicationFilterChain.java:215)
> > >> at org.apache.catalina.core.ApplicationFilterChain.doFilter(
> > > ApplicationFilterChain.java:188)
> > >> at org.apache.catalina.core.StandardWrapperValve.invoke(
> > > StandardWrapperValve.java:210)
> > >> at org.apache.catalina.core.StandardContextValve.invoke(
> > > StandardContextValve.java:174)
> > >> at org.apache.catalina.core.StandardHostValve.invoke(
> > > StandardHostValve.java:127)
> > >> at org.apache.catalina.valves.ErrorReportValve.invoke(
> > > ErrorReportValve.java:117)
> > >> at org.apache.catalina.core.StandardEngineValve.invoke(
> > > StandardEngineValve.java:108)
> > >> at org.apache.catalina.connector.CoyoteAdapter.service(
> > > CoyoteAdapter.java:151)
> > >> at org.apache.coyote.http11.Http11Processor.process(
> > > Http11Processor.java:870)
> > >> at
> > >
> >
> org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processCon
> > > nection
> > > (Http11BaseProtocol.java:665)
> > >> at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(
> > > PoolTcpEndpoint.java:528)
> > >> at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(
> > > LeaderFollowerWorkerThread.java:81)
> > >> at
> org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(
> > > ThreadPool.java:685)
> > >> at java.lang.Thread.run(Unknown Source)
> > >> I tried with different test plans and with different number of
> > > threads/users in my test but basically i get this exception since 50
> > users.
> > >> I do the following in my test paln:
> > >> Enter to the page
> > >> Lookup for some data with an autocompleter
> > >> Input another data in a textbox
> > >> insert the previous information in a list that is a property of the
> > action
> > > related to the page( in my code ia have an action per page)
> > >> The list is displayed in a <table> in my page using <s:iterator>
> > >> Delete the item recently added to the list.
> > >> By the way my action is in the session.
> > >> Maybe the problem is my code, so please i want your opinion about
> this
> > > situation. I have made another stress test in webapps without struts2
> > and i
> > > never had this exception.
> >
> >
> >
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> >
>
--
Eduardo Dela Rosa
