The container manages a pool of message-driven beans for the concurrent processing of a stream of messages. The sun-ejb-jar.xml file contains the elements that define the pool (that is, the bean-pool element):
steady-pool-size
resize-quantity
max-pool-size
pool-idle-timeout-in-seconds
For more information about sun-ejb-jar.xml, see The sun-ejb-jar.xml File.