requires that at Transaction completion, the container closes (or returns
to cache), the transaction-scoped
persistence context. What is supposed to happen when the JTA transaction
completes in a different thread than the
application thread? For example, if a background thread calls the
Synchronization.afterCompletion() because the tx
timeout period has been exceeded (as some Transaction Managers may do), its
not exactly thread-safe to call
EntityManager.close() (see ). Specifically, the application could be in
the middle of a persist or some other
EntityManager method, when EntityManager.close() is called.
Related to the above, if a JTA transaction rollback occurs in a background
thread , how are the managed entities
expected to be detached without violating the EntityManager thread-safety ?
There may be vendor specific solutions but shouldn't we (JPA spec eg) account
for the interaction of thread-unsafe
persistence contexts and the JTA Synchronization.afterCompletion that may be
invoked in non-application (background)
 7.9.1 Container Responsibilities - After the JTA transaction has
completed (either by transaction commit or
rollback), the container closes the entity manager calling
 7.2 Obtaining an EntityManager - An entity manager must not be shared
among multiple concurrently executing threads,
as the entity manager and persistence context are not required to be
threadsafe. Entity managers must only be accessed
in a single-threaded manner.
 7.9.2 Provider Responsibilities - When the JTA transaction rolls back,
the provider must detach all managed entities
if the persistence context is of type SynchronizationType.SYNCHRONIZED or has
otherwise been joined to the transaction.
[jsr338-experts] Re: transaction-scoped persistence context being closed at JTA transaction completion time from non-application thread ...