Fail Fast Vs Fail Safe Iterators In Java

Fail Fast Vs Fail Safe Iterators In Java :

Fail-Fast Iterators	Fail-Safe Iterators
Fail-Fast iterators doesn’t allow modifications of a collection while iterating over it.	Fail-Safe iterators allow modifications of a collection while iterating over it.
These iterators throw ConcurrentModificationException if a collection is modified while iterating over it.	These iterators don’t throw any exceptions if a collection is modified while iterating over it.
They use original collection to traverse over the elements of the collection.	They use copy of the original collection to traverse over the elements of the collection.
These iterators don’t require extra memory.	These iterators require extra memory to clone the collection.
Ex : Iterators returned by ArrayList, Vector, HashMap.	Ex : Iterator returned by ConcurrentHashMap.