https://issues.apache.org/bugzilla/show_bug.cgi?id=51919
--- Comment #9 from Sebb <s...@apache.org> 2011-10-01 11:44:23 UTC --- (In reply to comment #8) > (In reply to comment #4) > > Cookies are currently stored in an ArrayList. The Javadoc says: > > > > "If multiple threads access an ArrayList instance concurrently, and at least > > one of the threads modifies the list structurally, it must be synchronized > > externally." > > > > This means that all accesses must be synchronised, not just modifications. > > > > The simplest way to do this would be to use Collections.synchronizedList. > > > > There is a concurrent list: > > > > http://download.oracle.com/javase/6/docs/api/java/util/concurrent/CopyOnWriteArrayList.html > > > > However this is only worth it if there are many more reads than writes. > > I'm not sure that's the case with Cookies. > > > > == > > > > An alternative might be to somehow defer the cookie setting to the main > > sample > > thread. It should not matter if the cookies are stored after all the > > resources > > have been read, because the order of responses is not guaranteed. Any > > cookies > > required by the resource download must exist before the request is made. > > Hello Sebb, > I knwo about this rule regarding the need to synchronize all methods. > But sometimes it is acceptable to only synchronize methods that modify, the > trade-off will be that: > - You can get obsolete informations (size, element removed) > - But collection state will stay OK. A thread that reads the collection can still experience ConcurrentModificationException if it does not use synch. > That's the approach I chose. > > I used it a lot of times and I am sure it works on ArrayList. It can have > issues with LinkerList but not arrayList. I think you have been lucky. > I think Collections.synchronizedList() can have performance impact, I am not > sure I understand what you want to do, you want to modify CollectionProperty > to > use a Collections.synchronizedList() wrapper ? I know it has an impact; that's why we should not rush into partial fixes. But I intended it only for the Cookie ArrayList. -- Configure bugmail: https://issues.apache.org/bugzilla/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are the assignee for the bug. --------------------------------------------------------------------- To unsubscribe, e-mail: notifications-unsubscr...@jakarta.apache.org For additional commands, e-mail: notifications-h...@jakarta.apache.org
