Wikipedia
OpenSSO
OpenSSO was an open source access management and federation server platform (SSO acronym stands for Single Sign-On ).
Announced by Sun Microsystems in July 2005, OpenSSO was based on Sun Java System Access Manager, and was the core of Sun's commercial access management and federation product, OpenSSO Enterprise (formerly Sun Access Manager and Sun Federation Manager).
Oracle completed their acquisition of Sun Microsystems in February 2010 and shortly thereafter removed OpenSSO downloads from their website in an unannounced policy change. OpenSSO was forked as OpenAM, developed and supported by ForgeRock.