People interested in this should also have a look at the E language. It is also a secure programming language. It goes a different route - there are no policies, instead a reference to an object gives the right to access the object. This works because there is no global access to objects. They call it object capability security. There is also a java compiler addon to enforce capability security. The relevant website is http://www.elang.org/
Has anyone read Anathem yet? It is a difficult read, mainly because Stephensons goes on a 100-page philosophical tangent, but it is very rewarding. It also contains the most realistic space battle description evar. Definitely my favourite science fiction novel, although I am not a big sci fi fan. I tried reading Asimove short stories, and found myself bored out of my mind. Well, science fiction does not age well.