single sign on

I'm working on a SSO solution.
The situation is as follows: we are working on a Ruby On Rails team
and our partners are working on a J2EE application.
We want single sign-on solution for this. It's more appropriate that
the final solution supports all triple As (Authorization,
Authentication and Audition).
Can you please help us to reach a solution. I've seen freeradius but
it's somehow complex and I can't interact with it from a ruby client.

I have two http bassed applications, one of them is on java spring and
the other one is rails. These two apps share same database and need to
have integrated authorization/authentication. The user management UI
should be integrated in java spring application and rails application
should use it as a service.

Hi Ehsan,

I am too investigate on the same. i.e if you enter youtube, gmail, or google+ url and click for signin. It will redirect to common page for signin. Once you authorized user you will redirected to corresponding domain.

I think you can use oauth.

Thanks,
Senthil srinvasan