I have the following classes

abstract class O{...}

class A extends O{...}
class B extends O{...}

class foo{
O bar;
...
}

Now, I have a list L of instances of A and B. I want to create a list
of instances of foo where each instance has a copy of one of the
objects in L, as I will be messing with the objects but want to keep
the original data.

Normally, I'd do something like: (yes, I should be using an iterator)

O x;
while(x = (O)(L.next))
fooList.add(new foo(x));

The problem I'm running into is that since everything is a reference,
I need to create a copy of each object I pass into the foo constructor
or I'll be messing with the original. Since I don't know what the
actual class for each object is, I can't create a new object of the
proper class, so I have to use the superclass.

I kludged a solution by copying the initial list and pointing the
fooList at it. Is there a nicer way to do this, or am I missing
something fundamental?