Lightweight Message Bus library [closed]

Question

I will be starting a small Java (GWT really) project in the near future and I am at "information gathering" phase.

Q: Is there a lightweight Message Bus library written in Java?

My requirements are lightweight too :-)

1. async (no need for sync)
2. multicast and point-to-point
3. no strict message ordering
4. message "envelope" ideally "owned" by Message Bus (i.e. in terms of life-cycle management)
5. localized delivery (i.e. not inter-process nor inter-node)

Update: It seems that GWT now supports an integrated "event bus".

Answer 1

Have a look at eventbus.

(Link fixed; thanks to jldupont to point that out).