I would like to write a application for mobile devices (blackberry and android). Is there a (free) client to connect to a MOM? The MOM should guarantee message delivery even if the connection is closed and reopened.
We thought about using jms, but is there a free client that works on these platforms? XMPP could be another alternative.
ActiveMQ (from Apache) works really well. It respects the JMS specification and is totally free. The generated stubs and skeletons are in Java, so that would work on droids for sure.
ActiveMQ also have delivery guarantees that you can configure as you like (you can even get guaranteed delivery for topics, even if that's not in the JMS spec. That call it durable subscriber).