java - Do we ever need to use Iterators on ArrayList?

Question

Yesterday, when I was answering to question getting ConcurrentModificationException error while using iterator and remove I added a notice that

It's not a good idea to use iterators when you have ArrayLists.

You do not need to deeply understand that question to answer on that one.

There, I got two comments that I'm wrong.

My arguments:

1. The code is much less readable with iterators.

2. There is a possibility to raise ConcurrentModificationException that is hard to debug.

Can you please explain?

Question: Do we ever need to use Iterators on ArrayList?

UPD

This is about explicitly using Iterator.

Answer 1

A big use case of iterators with ArrayLists is when you want to remove elements while iterating. You have only three safe solutions :

• use an iterator and its remove method
• copy the elements you want to keep in another list
• jungle with indexes

Assuming you don't add while iterating, using the iterator is a mean to avoid the ConcurrentModificationException.

The readability argument is subjective. Personally I don't find a cleanly declared iterator less readable. And it doesn't really matter as the iterator is the safe way to iterate and remove at the same time.