[richfaces-issues] [JBoss JIRA] Closed: (RF-3631) ConcurrentModificationException during session serialization

ConcurrentModificationException during session serialization ------------------------------------------------------------ Key: RF-3631 URL: http://jira.jboss.com/jira/browse/RF-3631 Project: RichFaces Issue Type: Bug Components: docs updated Affects Versions: 3.2.0, 3.1.5 Environment: JBboss 4.2.2.GA Seam 2.0.2.SP1 JDK 1.5.0_15 Windows XP Pro SP2 Reporter: Stanimir Stamenkov Assigned To: Aleksej Yanul Fix For: 3.1.6 Attachments: test-cluster-session.ear Concurrent requests cause java.util.ConcurrentModificationException during session serialization in cluster environment. I've initially posted this issue to the RichFaces users forum, but then posted to the Clustering/JBoss, too: http://www.jboss.com/index.html?module=bb&op=viewtopic&t=136590 where I've got feedback I'm on the right track my problem is probably caused by the RichFaces (Ajax4Jsf) library. Basically the web session gets modified while it is been serialized when concurrent requests are made. bstansberry(a)jboss.com have written: "The session management layer does not prevent concurrent access to the session. The session's internal data structures can deal with concurrency (e.g. the attribute map is a ConcurrentHashMap) but if the objects you'll store in it are going to be accessed concurrently, they'll need to be thread safe or have access to them synchronized." I've prepared minimal test case (I'm about to attach) demonstrating the problem. I've tried it with both RichFaces 3.1.5.GA (part of Seam 2.0.2.SP1) and RichFaces 3.2.0.SR1 (which I'm using with my application).