The non-propagating (REQUIRES_NEW) ensures that the transaction is always new. I supose that the problem using the getUserTransaction is that if the transaction is already running, and I use that, may appears a concurrency problem. But using always a new transaction, could give me problems of performance?
I'm implementing a java backed webscript. A lot of users will use my service, and for each one the code will use 4 o 5 transactions. What's the better option? When is the best option use getNonPropagatingUserTransaction vs getUserTransaction?
Thanks!