I was talking about messaging externally to the JVM, ie with other
processes on other machines. Principally it would mean JMS, but my work is
based on the J2EE Connector Architecture (JCA) 1.5 spec which can support
other kinds of asynchronous messaging, eg MSMQ, ebXML or even SMTP.
By asynchronous I'm referring to a model where the external system (eg the
JMS queue/topic) notifies the OSGi runtime immediately when a message is
available. This is in contrast with synchronous messaging where you must
poll periodically for new messages. Previously asynchronous message
receipt has only been possible inside a J2EE application server*.
The OSGi EventAdmin service is very important and useful but it is only
used for event notification within the JVM.
Kind regards,
Neil
*Actually that's not strictly true, there is some support in the Spring
2.0 betas for asynchronous message receipt, but not with dynamic
MessageListener registration and hotswapping.