What will happen if thread limit exceeds and new message arrives: i.e., for example, listener may process only 5 threads simutanously (maxThreads=5).
What will happen if 6th message arrives for processing, but all threads are busy.
Will it be processed when one of threads will be free or message will be lost?
Didn't you ask this question only a week or so ago? ;)
Anyway... the backlog of messages will be processed as the busy threads become free again. They will not be dropped/lost.