Access to own private fields of a subclass object

Question

This construct just does not compile:

class A {
    private int data;
    public static int process(B b) {
        return b.data;// error here: 'data has private access in A'
    }
}
class B extends A {}

Of course, this problem can be solved easily by hand (cast b in A, field protection, etc.). But the question is, why does Java not allow such a design? I thought that the compiler should know that B is a subclass of A, so methods A should have access to private fields.

The only possible problem that I can think of is that if B has its own data field, the compiler does not need to know in which field we want to access, but for what we inherit, right?

Answer 1

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