TestSuperToSubclass

public class TestSuperToSubclass {

    public static void main(String[] args) {
        final TestSuperToSubclass instance = new SubClass();
        instance.superClassMethod();
    }

    private void superClassMethod() {
        if (this instanceof SubClass) {
            System.out.println(((SubClass) this).field);
        } else {
            System.err.println("Unexpected subclass type: " + this.getClass().getName());
        }
    }
}

class SubClass extends TestSuperToSubclass {
    protected String field = "Test value.";
}