Sorry, this doesn't make sense to me. A private  method can quite happily access
public classes and their public members.

It is the reverse which is true - a private method cannot be accessed by other
classes (only from within its own class).

This makes "main" inaccessible outside "Test" and therefore in theory
inaccessible to the run-time environment (although I can imagine some run-time
environments not bothering to check for this).