The SDK contains all the material you need to use SocialAuth java library. The directories are as follows:
dist - This contains socialauth-x.x.jar, socialauth-filter-x.x.jar, socialauth-seam-x.x.jar, socialauth-cdi-x.x.jar, socialauth-spring-x.x.jar and socialauth-cmd-utility. While creating java application you have to include socialauth-x.x.jar in your application. Rest depends on what type of java application you are building. It also includes properties file. oauth_consumer.properties is also necessary to configure application key/secret of various providers.
dependencies - This contains commons-logging-1.1.jar, json-20080701.jar and openid4java.jar. You need to include all these jars in your any application. Please note that other dependecies are also required as per your framework e.g for struts you have to include struts framework libraries.
src - This contains the various socialauth Eclipse project if you would like to debug or you need to make some changes. Most of the time you should not need to.
examples - This contains struts, spring, seam examples that we have built for you showing how the SDK can be used to build java application.
javadoc - Documentation for SocialAuth different libraries.