This service allows you to use your java.net account as an OpenID. It is of the following format:
While this can be used to let you login to any web sites that support OpenID as an identity, the primary use case is to enable projects on java.net to host additional tools externally on their own, but still use java.net for authentication, for better integration. That is, such peripheral systems can follow the OpenID protocol and request the user to sign in by using their java.net OpenID (and if necessary, you can check their committer status against your project by using libraries like java.net tasks.
This service is not currently officially endorsed by java.net (as evident in its domain name), but we are working on the official endorsement.
If you have problems or ideas, contact Kohsuke Kawaguchi.