I don't understand the design of inner class private member

Question

This is a question about the java language specification of inner classes.
In the java langage specification document, we read
If the member or constructor is declared private,
then access is permitted if and only if it occurs
within the body of the top level class (�7.6)
that encloses the declaration of the member.
This allows following code :
  public class PrivateTest {
    public PrivateTest()
      Hello hello = new Hello();
      System.out.println(hello.secret);
    class Hello
       private String secret = "This is a secret";
  } wherein accessing the private secret field is allowed
from into the PrivateTest enclosing class.
My questions are :
a) It seems that private methods or constructors of
inner classes have no meaning, we could also declare
them as public. True or false ?
b) Is there any reason that Java bypass this private
mechanism ?
c) Why is the above definition not written with
"first enclosing" instead of "top level" ?
Thanks in advance

Answer 1

Private methods and constructors of an inner class can only be accessed within the outer class. Other classes can't instantiate it or use the private methods.
You can also make your inner class private, so it is not possible to refer to the class from outside (and thereby another way of preventing it from being instantiated).
So it does matter which access modifiers you use.
I think top level is more precise than first enclosing, because you can have inner classes in inner classes, which are still available for the top level class (haven't tested this).