Java Programming - Objects and Collections - Discussion

I would also say that the statement "the elements in the collection are ordered" is deceiving or at least not very clear. They certainly keep their position as long as only insertions are performed on the list (which is of course not guaranteed and the question doesn't say anything about how it will be used). But they most certainly will not be in their natural ordering.

B and C are definitely false. So answer D seems the most correct. All elements have a unique key (namely their index). Although if we consider multiple int's with the same values, than perhaps this statement is a bit problematic as well.

How can be an element in the order of ArrayList?

Wrong Answer!

ArrayList elements are indexed. :)