[wildfly-dev] Issues accessing UserTransaction in WildFly

[Jaikiran Pai]

 >> Right the real question is what is Seam using the UT for. There is 
only one method on that is “safe” with CMT (getting the status), and 
that isn’t all that useful.

Looking at that stacktrace [1] and the code in Seam [2], it appears that 
Seam wants to register a transaction synchronization if a transaction is 
active. Unfortunately, a lot of libraries (including Seam) use the 
UserTransaction API (UserTransaction.getStatus()) to check if a 
transaction is active. The right way to do it is using the 
TransactionSynchronizationRegistry which is available and portable (as 
mandated by spec) under the java:comp/TransactionSynchronizationRegistry 
JNDI name. The TransactionSynchronizationRegistry has a 
getTransactionStatus() method which can be used to check the transaction 
status in the current (thread) context 
http://docs.oracle.com/javaee/5/api/javax/transaction/TransactionSynchronizationRegistry.html#getTransactionStatus%28%29. 
Usage of this API is rarely explained and applications/libraries keep 
using UserTransaction instead.

To answer the other question as to why this started showing up now and 
not in earlier versions, the code in Seam tries to deal with this exact 
situation by catching a specific (NameNotFoundException) while doing a 
UserTransaction lookup [3]. Notice that in that code [3], it doesn't 
deal with any other exception other than NameNotFoundException although 
that code does realize that using UserTransaction for what it's doing 
can run into problems (the comments there indicate something along those 
lines). So my guess is that, in previous version of AS, we used to throw 
a NameNotFoundException in this specific case and now we are throwing a 
IllegalStateException [4]. Maybe in WildFly, to prevent existing 
libraries like Seam from breaking, we could just change this bit to 
throw NameNotFoundException instead of IllegalStateException (although I 
don't remember if the TCK tests for the exact exception type in this case).


[1]

	at org.jboss.seam.transaction.Transaction.instance(Transaction.java:39) [jboss-seam.jar:2.2.2.Final]
	at org.jboss.seam.persistence.ManagedPersistenceContext.joinTransaction(ManagedPersistenceContext.java:120) [jboss-seam.jar:2.2.2.Final]
	at org.jboss.seam.persistence.ManagedPersistenceContext.getEntityManager(ManagedPersistenceContext.java:112) [jboss-seam.jar:2.2.2.Final]


[2] http://grepcode.com/file/repository.jboss.org/nexus/content/repositories/releases/org.jboss.seam/jboss-seam/2.2.2.Final/org/jboss/seam/persistence/ManagedPersistenceContext.java#118

[3] http://grepcode.com/file/repository.jboss.org/nexus/content/repositories/releases/org.jboss.seam/jboss-seam/2.2.2.Final/org/jboss/seam/transaction/Transaction.java#77

[4] Caused by: java.lang.IllegalStateException: JBAS014237: Only session and message-driven beans with bean-managed transaction demarcation are allowed to access UserTransaction

P.S: A big congratulations on the WildFly 8.0 Final release! :) Although haven't posted here so far, I've been lurking this list. Good luck with the next releases.


-Jaikiran