What class to use

[ryucc]

What class to sub

For all

1. The runtime class:
   Ideal choice, immune to later casting.
2. Parent class

Interception

Requirements:

1. Non-final (Mockito can bypass final sometimes. but non final for now.)
2. private is fine
3. non visible is fine.

Code generation

User nodes:

1. Can be final
2. non private
3. visible to package