Your question falls under the "suck it and see" category.
You are also in the wrong forum. This is a question about JCA.
Whoever wrote the statement in your quote, obviously never heard of user transactions.
And neither have you.
Why are you using Spring when it exposes you to specifications you don't
understand and you have no other spec to guide you?
I'll answer your question with a question.
Why should JCA care who makes the thread's transaction association?
And a warning:
If you are not doing something similar to EJB transaction demarcation all bets are off.
To tell you the truth you are very ill-mannered person and u better need to see some doctor to get the screws of your head a bit tighter. I damn care for your app server and a mad person like you. You mental sick, ill-mannered , ill-literate