Java private field access possible when having a reference?

Question

I came across the following "strange" feature today - if you have a reference to an object from the class A in the body of the class A you can access the private fields of this object - i.e:

public class Foo{
   private int bar;
   private Foo foo;
   public void f()
   {
       if(foo.bar == bar) // foo.bar is visible here?!
       {
            //
       }
   }
}

Anyone has a good explanation about this?

Answer 1

Access modifiers work at the class level, not at the instance level: all code in the same class can access private members of all instances of the class.

Nothing particularly strange about it.

Answer 2

It is intended to be this way.

Citing the Java Language Specification:

A member (class, interface, field, or method) of a reference (class, interface, or array) type or a constructor of a class type is accessible only if the type is accessible and the member or constructor is declared to permit access:

• ...
• (Otherwise,) 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.
• ...