JDK use cases for friend constraints

[Mandy Chung]

  I have analyzed the JDK implementation and determine if there are any 
internal interfaces that are used by the module containing it and also 
required by other JDK module.  As they are solely for internal use and 
unsupported, friend constraints support will be useful so that we can 
restrict our internal interfaces for specific modules to use.

http://cr.openjdk.java.net/~mchung/jigsaw/analysis/friend-constraint-use-cases.html
     This document describes the JDK use cases for it.

Mandy