OA33442: ConcurrentModificationException while stress testing at server s tartup

APAR status

• Closed as program error.

Error description

• Env: WAS 6.1 on z/OS 6.1.0.21
  During a stress test of Portal 6.1 server, six
  Rational Performance Tester agents were used with zero think
  time. At the very
  beginning of the test, a ConcurrentModificationException was
  encountered:
  
  EJPEJ0066E: The portlet could not be
  rendered.java.util.ConcurrentModificationException
    at
  java.util.LinkedList$ListItr.checkForComodification(LinkedList.j
  va:632)
    at java.util.LinkedList$ListItr.next(LinkedList.java:567)
    at
  com.ibm.ws.portletcontainer.PortletContainerInvokerCollaboratorC
  ainImpl.doCollaborator(PortletContainerInvokerCollaboratorChain
   Impl.java:57)
    at
  com.ibm.ws.portletcontainer.PortletContainerImpl.renderPortlet(P
  rtletContainerImpl.java:89)
    at
  com.ibm.ws.portletcontainer.pcinvoker.PortletInvokerImpl$2.run(P
  rtletInvokerImpl.java:100)
    at
  java.security.AccessController.doPrivileged(AccessController.jav
  :246)
    at
  com.ibm.ws.portletcontainer.pcinvoker.PortletInvokerImpl.invokeR
  nder(PortletInvokerImpl.java:96)
    at
  com.ibm.wps.pe.pc.waspc.core.impl.PortletInvokerImpl$1.invoke(Po
  tletInvokerImpl.java:93)
    at
  com.ibm.wps.pe.pc.waspc.core.impl.PortletInvokerImpl.invoke(Port
  etInvokerImpl.java:176)
    at
  com.ibm.wps.pe.pc.waspc.core.impl.PortletInvokerImpl.invokeRende
  (PortletInvokerImpl.java:91)
    at
  com.ibm.wps.pe.pc.waspc.PortletContainerImpl.renderPortlet(Portl
  tContainerImpl.java:116)
    at
  com.ibm.wps.pe.pc.PortletContainerImpl.doRenderPortlet(PortletCo
  tainerImpl.java:641)
    at
  com.ibm.wps.pe.ext.render.AbstractRenderManager.performService(A
  stractRenderManager.java:264)
    at
  com.ibm.wps.pe.pc.PortletContainerImpl.renderPortlet(PortletCont
  inerImpl.java:132)
    at
  com.ibm.wps.engine.tags.PortletRenderTag.doStartTag(PortletRende
  Tag.java:179)
    at
  com.ibm._jsp._Control._jspx_meth_portal$1skin_portletRender_0(_C
  ntrol.java:922)
    at com.ibm._jsp._Control._jspService(_Control.java:516)
    at
  com.ibm.ws.jsp.runtime.HttpJspBase.service(HttpJspBase.java:87)
    at
  javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
  

Local fix

Problem summary

• ConcurrentModificationException while stress testing at server
  startup - Env: WAS 6.1 on z/OS 6.1.0.21
  
  During a stress test of Portal 6.1 server, six Rational
  Performance Tester agents were used with zero think time. At the
  very beginning of the test, a ConcurrentModificationException
  was encountered:
  
  EJPEJ0066E: The portlet could not be
  rendered.java.util.ConcurrentModificationException
    at
  java.util.LinkedList$ListItr.checkForComodification(LinkedList.j
  ava:632)
    at java.util.LinkedList$ListItr.next(LinkedList.java:567)
    at
  com.ibm.ws.portletcontainer.PortletContainerInvokerCollaboratorC
  hainImpl.doCollaborator (PortletContainerInvokerCollaboratorChai
  nImpl.java:57)
    at
  com.ibm.ws.portletcontainer.PortletContainerImpl.renderPortlet(P
  ortletContainerImpl.java:89)
    at
  com.ibm.ws.portletcontainer.pcinvoker.PortletInvokerImpl$2.run(P
  ortletInvokerImpl.java:100)
    at
  java.security.AccessController.doPrivileged(AccessController.jav
  a:246)
    at
  com.ibm.ws.portletcontainer.pcinvoker.PortletInvokerImpl.invokeR
  ender(PortletInvokerImpl.java:96)
    at
  com.ibm.wps.pe.pc.waspc.core.impl.PortletInvokerImpl$1.invoke(Po
  rtletInvokerImpl.java:93)
    at
  com.ibm.wps.pe.pc.waspc.core.impl.PortletInvokerImpl.invoke(Port
  letInvokerImpl.java:176)
    at
  com.ibm.wps.pe.pc.waspc.core.impl.PortletInvokerImpl.invokeRende
  r(PortletInvokerImpl.java:91)
    at
  com.ibm.wps.pe.pc.waspc.PortletContainerImpl.renderPortlet(Portl
  etContainerImpl.java:116)
    at
  com.ibm.wps.pe.pc.PortletContainerImpl.doRenderPortlet(PortletCo
  ntainerImpl.java:641)
    at
  com.ibm.wps.pe.ext.render.AbstractRenderManager.performService(A
  bstractRenderManager.java:264)
    at
  com.ibm.wps.pe.pc.PortletContainerImpl.renderPortlet(PortletCont
  ainerImpl.java:132)
    at
  com.ibm.wps.engine.tags.PortletRenderTag.doStartTag(PortletRende
  rTag.java:179)
    at
  com.ibm._jsp._Control._jspx_meth_portal$1skin_portletRender_0(_C
  ontrol.java:922)
    at com.ibm._jsp._Control._jspService(_Control.java:516)
    at
  com.ibm.ws.jsp.runtime.HttpJspBase.service(HttpJspBase.java:87)
    at
  javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
  

Problem conclusion

• Added synchronization points to moderate access of threads to
  LinkedLists containing the collaborators.
  
   Note: Run osgiCfgInit wihin AppServer/bin directory
  
  
  Failing Module(s):
     Portlet Container
  
  Affected Users:
     All Users
  
  Version Information:
      Portal Version(s): 6.1.0.0
       Pre-Requisite(s):
        Co-Requisite(s): ---
  
      Portal Version(s): 6.1.0.1
       Pre-Requisite(s):
        Co-Requisite(s): ---
  
      Portal Version(s): 6.1.0.2
       Pre-Requisite(s):
        Co-Requisite(s): ---
  
  Platform Specific:
     This fix applies to all platforms.
  
  A fix is available from Fix Central:
  
  http://www.ibm.com/eserver/support/fixes/fixcentral/swgquickorde
  r?apar=PK81131&productid=WebSphere%20Portal&brandid=5
  
  You may need to type or paste the complete address into your Web
  browser.
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

  PK81131

• APAR is sysrouted TO one or more of the following:

Fix information

• Fixed component name

  WEBSPH PORTAL Z

• Fixed component ID

  5655R1700

Applicable component levels

• R610 PSY