Rhino: restrict Java packages that can be accessed from JavaScript

When embedding a JavaScript interpreter (Rhino) into a Java application (to be able to script that application), how would one go about restricting the Java packages that are available to scripts? For example, only "java.lang.*" should be accessible.

From stackoverflow

• A method for blocking access to certain packages and classes (including through reflection) in Rhino is described here. The important interface is ClassShutter which provides access control for Rhino's LiveConnect support.

  Nathan Voxland : Ironically, the link to codeutopia.net about blocking access is returning 403 Forbidden for me