This really looks like page being accessed from multiple threads, but it's quite weird. The serialization is done in request thread and pagemap is locked during request.
-Matej On Thu, Dec 18, 2008 at 2:35 PM, leok <leo...@gmail.com> wrote: > > Interesting. I wonder if this error occurs when page components are being > modified by Ajax while being serialized, e.g. page.addOrReplace(). If so, > this is kind of an ugly bug. What I don't know yet is how "harmful" this bug > is, i.e. does this error leave Wicket in a horribly inconsistent state? > > > > Xhelas wrote: >> >> Same symptoms using wocket 1.4-rc1. >> >> Regards >> >> Alexandre >> >> >> leok wrote: >>> >>> I was poking through some logs, and I noticed a few rare instances of >>> this exception: >>> >>> java.util.ConcurrentModificationException >>> at >>> java.util.LinkedHashMap$LinkedHashIterator.nextEntry(LinkedHashMap.java:365) >>> at java.util.LinkedHashMap$KeyIterator.next(LinkedHashMap.java:376) >>> at java.util.HashSet.writeObject(HashSet.java:254) >>> at sun.reflect.GeneratedMethodAccessor3239.invoke(Unknown Source) >>> at >>> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) >>> at java.lang.reflect.Method.invoke(Method.java:585) >>> at >>> java.io.ObjectStreamClass.invokeWriteObject(ObjectStreamClass.java:917) >>> at >>> java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1344) >>> at >>> java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1295) >>> at >>> java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1084) >>> at >>> java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1380) >>> at >>> java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1352) >>> at >>> java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1295) >>> at >>> java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1084) >>> at >>> java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1380) >>> at >>> java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1352) >>> at >>> java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1295) >>> at >>> java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1084) >>> at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:307) >>> at java.util.HashMap.writeObject(HashMap.java:1328) >>> at sun.reflect.GeneratedMethodAccessor3234.invoke(Unknown Source) >>> at >>> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) >>> at java.lang.reflect.Method.invoke(Method.java:585) >>> at >>> java.io.ObjectStreamClass.invokeWriteObject(ObjectStreamClass.java:917) >>> at >>> java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1344) >>> [..snip..] >>> at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:307) >>> at >>> org.apache.wicket.util.io.IObjectStreamFactory$2.writeObjectOverride(IObjectStreamFactory.java:117) >>> at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:303) >>> at >>> org.apache.wicket.util.lang.Objects.objectToByteArray(Objects.java:1091) >>> at >>> org.apache.wicket.protocol.http.pagestore.AbstractPageStore$PageSerializer.getPageReplacementObject(AbstractPageStore.java:278) >>> at org.apache.wicket.Page.writeReplace(Page.java:1299) >>> at sun.reflect.GeneratedMethodAccessor6627.invoke(Unknown Source) >>> at >>> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) >>> at java.lang.reflect.Method.invoke(Method.java:585) >>> at >>> java.io.ObjectStreamClass.invokeWriteReplace(ObjectStreamClass.java:1004) >>> [..snip..] >>> at >>> org.apache.wicket.util.lang.Objects.objectToByteArray(Objects.java:1091) >>> at >>> org.apache.wicket.protocol.http.pagestore.AbstractPageStore.serializePage(AbstractPageStore.java:197) >>> at >>> org.apache.wicket.protocol.http.pagestore.DiskPageStore.storePage(DiskPageStore.java:811) >>> at >>> org.apache.wicket.protocol.http.SecondLevelCacheSessionStore$SecondLevelCachePageMap.put(SecondLevelCacheSessionStore.java:332) >>> >>> I'm using Wicket 1.3.5. It seems there might be some strange racing >>> happening while pages are being serialized. >>> >>> EDIT: I actually posted before completing my message. I meant to add - >>> where would there be non thread-safe modifications to the serialized >>> page? I presume that the there must be some sort of lock on the object >>> when it's being serialized. More importantly - how "harmful" is this >>> exception? >>> >> >> > > -- > View this message in context: > http://www.nabble.com/java.util.ConcurrentModificationException-inorg.apache.wicket.protocol.http.SecondLevelCacheSessionStore%24SecondLevelCachePageMap.put-tp21062585p21072905.html > Sent from the Wicket - User mailing list archive at Nabble.com. > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: users-unsubscr...@wicket.apache.org > For additional commands, e-mail: users-h...@wicket.apache.org > > --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@wicket.apache.org For additional commands, e-mail: users-h...@wicket.apache.org
