This is the full Active Objects library, if you don't know which one to use, you probably want this one.

An OSGi bundle that provides a service that allows plugins to persist objects using the ActiveObjects framework

ActiveObjects Plugin API

This is a library for Active Objects users to depend on for their own testing.

PSMQ - Provides Pretty Simple Message Queueing

PSMQ Rest - Provides Pretty Simple Message Queueing over REST