Classier Puzzlers - Java Puzzlers: Traps, Pitfalls, and Corner Cases - page 194

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Puzzle 66: A Private Matter
In this program, a subclass field has the same name as a superclass field. What does the program
print?
class Base {
public String className = "Base";
}
class Derived extends Base {
private String className = "Derived";
}
public class PrivateMatter {
public static void main(String[] args) {
System.out.println(new Derived().className);
}
}
Solution 66: A Private Matter
A superficial analysis of the program might suggest that it should print Derived , because that is
what is stored in the className field of each Derived instance. A deeper analysis suggests that
class Derived won't compile, because the variable className in Derived has more restrictive
access than it does in Base : It is declared private in Derived and public in Base . If you tried
compiling the program, you found that neither analysis is correct. The program doesn't compile, but
the error is in the class PrivateMatter .
Had className been an instance method instead of an instance field, Derived.className() would
have overridden Base.className() , and the program would have been illegal. The access modifier
of an overriding method must provide at least as much access as that of the overridden method [JLS