Shared API classes and interfaces used by both the back end (spi) and front end (service).
The Social Jar consists of a core set of packages that contain the lower level implementation of the component (o.a.s.social.core), and a set interface layers (o.a.s.social.opensocial) that represent areas of the component that are more outward facing. In addition there is a sample package which contains sample implementations of the service and spi.
This package contains classes that are outward facing, there are 4 main areas.