Should a parent class ever reference child classes?

Question

Good morning,

I inherited some legacy code at work and it is using a rather unusual design pattern. The only reference I could find on the forums to a similar patter

Answer 1

It's a very standard pattern in Java, and a common way to implement a Strategy pattern. You see it in the standard API all the time (Calendar vs. GregorianCalendar, NumberFormat vs. DecimalFormat and more).

That being said, with Dependency Injection being all the rage, such a pattern might indeed be replaced by a dedicated Factory class with a dedicate Factory interface, but in the absence of a larger design reason, I think the example you give is a perfectly reasonable design choice.