30.3. MDB and Consumer pool size

@MessageDriven(name = "MDBMessageSendTxExample",
  activationConfig =
    {
      @ActivationConfigProperty
        (propertyName = "destinationType", propertyValue = "javax.jms.Queue"),
      @ActivationConfigProperty
        (propertyName = "destination", propertyValue = "queue/testQueue"),
      @ActivationConfigProperty
        (propertyName = "maxSession", propertyValue = "1")
    })
@TransactionManagement(value= TransactionManagementType.CONTAINER)
@TransactionAttribute(value= TransactionAttributeType.REQUIRED)
public class MyMDB implements MessageListener
{ ....}