How to hide the internal structure of a Java API to the rest of the world

Question

i am developing a Java Api to do things (secret, uhhhh ;).

Is there a way to hide classes, and the internal structure of my API?

What i found until now:

Answer 1

There are two solutions to your question that don't involve keeping all classes in the same package.

The first is to use the Friend Accessor/Friend Package pattern described in (Practical API Design, Tulach 2008).

The second is to use OSGi.

Related Questions: 1, 2, 3, and 4.