Overriding applies to methods, not fields. Fields can be hidden, though. Add "System.out.println(s)" to your code and see what happens.
You may also find
https://coderanch.com/how-to/java/OverridingVsHiding interesting,although that's about methods, not fields.
In the future, please do not post such questions in the "Ranch Office" forum, it is not meant for technical questions. Instead, pick one of the many technical forums that is most appropriate for that question.