If you are using CDI’s conversations you will most likely have come across the dreaded BusyConversationException. The CDI 1.0 specification states that the container must ensure that only one request at a time may be associated with the conversation by blocking or rejecting subsequent requests.
OpenWebBeans will immediately reassign and throw a BusyConversationException if the conversation is currently held by another request. Weld on the other hand uses a 1 second timeout to obtain a lock on the conversation before reassigning the request and throwing a BusyConversationException. Although this makes it less likely to occur, if you are dealing with multiple waiting requests or long running processes, you will still encounter them.
Continue reading Synchronizing access to CDI Conversations