Treating classes as first-class objects

Question

I was reading the GoF book and in the beginning of the prototype section I read this:

This benefit applies primarily to languages like C++ that don't treat classes as first class objects.

I've never used C++ but I do have a pretty good understanding of OO programming, yet, this doesn't really make any sense to me. Can anyone out there elaborate on this (I have used\use: C, Python, Java, SQL if that helps.)

Answer 1

For a class to be a first class object, the language needs to support doing things like allowing functions to take classes (not instances) as parameters, be able to hold classes in containers, and be able to return classes from functions.

For an example of a language with first class classes, consider Java. Any object is an instance of its class. That class is itself an instance of java.lang.Class.