RRiBbit is the most advanced, versatile and easy to use Open Source Eventbus in the Java World. You can use it within a Java application, to have different classes/components talk to each other without needing dependencies on one another, and you can use it to communicate with other Java applications on other machines.

RRiBbit improves upon existing Eventbuses by being compatible with existing code and by allowing the listeners to send something back to the senders. That's why we like to use the term Request-Response-Bus.

Version 2.2.0 adds HTTP support to the already existing Java RMI and JMS support. This is seen as an important update for RRiBbit, since HTTP is the most widely used communication protocol. You can now use RRiBbit to let a Java program on one machine talk to a Java program on another machine via HTTP without relying on complex mechanisms such as Web Services or SOAP. In fact, you can just keep using your plain old Java Method calls!

We also made some other minor improvements. Please see www.rribbit.org/versions.html for more information.