With JMSRA, if the queue or topic used by a MDB is configured using the non-standard mappedName attribute then there is no need to specify the activation property destinationType
However if if the queue or topic used by a MDB is configured using the standard destinationLookup activation property then there is a need to specify the activation property destinationType:
There doesn't seem to be a good reason for this. Given that JMSRA is MQ-specific then if destinationLookup is specified it should be possible to use private API to determine whether the destination is a queue or topic.
Note that if the non-standard activation property destination is used to specify the physical queue or topic name then it will still be necessary to specify the destinationType property.