Limiting concurrent MDB pumping messages from a JMS (or MQ) queue (throttle)

you can use work managers with max-threads-constraint, or max-beans-in-free-pool : this is the ultimate source of truth... remember that by default you have only 16 concurrent beans registered as consumers on a queue:

https://docs.oracle.com/cd/E24329_01/web.1211/e24390/mdbtuning.htm#PERFM274