What is the difference between fail-fast and fail-safe iterator?

Difference between Fail Fast Iterator and Fail Safe Iterator The major difference is fail-safe iterator doesn’t throw any Exception, contrary to fail-fast Iterator. This is because they work on a clone of Collection instead of the original collection and that’s why they are called as the fail-safe iterator.

Is HashMap fail-fast?

Default iterators for Collections from java. util package such as ArrayList, HashMap, etc. are Fail-Fast. In the code snippet above, the ConcurrentModificationException gets thrown at the beginning of a next iteration cycle after the modification was performed.

What is fail-safe and fail-fast?

Fail-Safe. 1. Exception. Any changes in the collection, such as adding, removing and updating collection during a thread are iterating collection then Fail fast throw concurrent modification exception. The fail-safe collection doesn’t throw exception.

Is list iterator fail-fast?

The iterators returned by ArrayList iterator() and listIterator() methods are fail-fast: if the list is structurally modified at any time after the iterator is created, in any way except through the iterator’s own remove or add methods, the iterator will throw a ConcurrentModificationException .

What is fail safe and fail fast in HashMap?

The iterators returned by the iterator method of the collections returned by all of this class’s “collection view methods” are fail-fast: if the Hashtable is structurally modified at any time after the iterator is created, in any way except through the iterator’s own remove method, the iterator will throw a Also, what is fail safe and fail fast?

What’s the difference between fail fast and fail-safe iterators?

Fail-safe iterators means they will not throw any exception even if the collection is modified while iterating over it. Whereas Fail-fast iterators throw an exception (ConcurrentModificationException) if the collection is modified while iterating over it. Subsequently, one may also ask, what is fail fast in collection?

Is the iterator returned by ConcurrentHashMap weakly consistent?

Note (from java-docs) : The iterators returned by ConcurrentHashMap is weakly consistent. This means that this iterator can tolerate concurrent modification, traverses elements as they existed when iterator was constructed and may (but not guaranteed to) reflect modifications to the collection after the construction of the iterator.

What’s the difference between fail fast and fail safe in Java?

Any changes in the collection, such as adding, removing and updating collection during a thread are iterating collection then Fail fast throw concurrent modification exception. The fail-safe collection doesn’t throw exception. 2. 3. It’s work on actual collection instead.