Scripting: Collection object members are null?

Question

We are trying to validate the contents of a collection, and are having difficulty accessing individual members.
We have tried both using the iterator
Iterator iterator = collection.iterator();
while (iterator.hasNext()) {
Object element = iterator.next();
throw doc.createApplicationException("test",element);
And the .get() method of the collection variable that is supplied.
int i;
for (i=0;i<=collection.size();i++) {
  throw doc.createApplicationException("test",collection.get(i));
collection.size() shows that we have 2 members in the collection, but looping through them appears to return null objects.

Answer 1

We are simply writing a collection validation script in the E-sourcing web interface, which use Beanshell. No tool per se.
I tried this syntax and I still get an error on the line
fieldX = member.get(fieldX);
internal Error: null variable value
The complete code is
iterTest = collection.iterator();
for(member : iterTest){
  fieldX = member.get(fieldX);
  System.out.println("FieldX: " + fieldX);
collection.size is 2, so I know there's something in there.