如何在子类中公开受保护的静态字段？

Question

I have this code:

class A {
    protected static final String foo = "FOO";
}

class B extends A {
    public static final String foo;
}

I expect System.out.println(B.foo) to print FOO but it prints null .

I know that I can get around this by replacing the field declaration in B with a method like:

class B extends A {
    public static final String foo() { return foo; }
}

Is it possible to inherit a protected static field and make it public?

The class B is used as a mock object, and adding those parenthesis so the call is B.foo() instead of B.foo does not really matter, but I was just interested if it was possible to get rid of them, and if yes, if there is a good reason not to do that. Or if my approach is completely wrong in some other way.

Answer 1

I expect System.out.println(B.foo) to print FOO but it prints null .

That is because B.foo does not override A.foo ; instead, it shadows A.foo - in other words, B.foo is a new variable, separate from A.foo , that just happens to have the same name.

Variables cannot be overridden, and static methods cannot be overridden.

Only non-static methods can be overridden in a subclass.

Is it possible to inherit a protected static field and make it public?

No.