Question

I was wondering what it means to say a field is hidden between 2 java classes and
what it means when running code in terms of resulting output?

I have an abstract class with a protected static boolean field = false and a sub class
which has a boolean field with the same name but is not static and set to true.

If I had this code:

Superclass d = new subclass();

what would be the value of the boolean field in the superclass and the boolean field
in the subclass? Does subclass field stay as false after the assignment above?

Answer 1

static members are never overridden (and certainly not by non-static members). And since you should access them like this: ClassName.member there is also no need to worry about hiding them.

In your case, you would access the Superclass field like this: Superclass.field. And the field of a Subclass instance like this: subclass.field. If you have, however a Subclass instance in a Superclass variable like above, this code: d.field will access the static field defined in Superclass, which will be false in your case.

But this does not change the value of the Subclass instance, it just accesses the “wrong” member! You can verify this by putting the instance in d back into a Subclass variable and reading field again.