I recently discovered in a real application case that jMQTTBroker2 v2.02 is not really reliable (some messages arriving in large numbers in a short time cause errors and are not processed properly). I think it's related to the changes made in version 2.01, but the problem may have existed before. Official changes were made in version 0.13 (unreleased) of Moquette to fix flush problems.
You can easily see what's going wrong by using the Stress demo provided with jMQTTBrokerExtended v2.0.
You can easily see what's going wrong by using the Stress demo provided with jMQTTBrokerExtended v2.0.