I know that more-dynamic-than-Java languages, like Python and Ruby, often allow you to place objects of mixed types in arrays, like so:
[\"hello\", 120, [\"w
There is no reason not to support heterogeneous lists. It's a limitation for technical reasons, and we don't like those.
Not everything needs to be a class!
In Python, a class is basically a souped up dictionary with some extra stuff anyway. So making a class User is not necessarily any clearer than a dictionary {"name": ..., "id": ...}.