Why iterator is fail-fast?

Iterator on ArrayList, HashMap classes are some examples of fail-fast Iterator. This is because, they operate on the clone of the collection, not on the original collection and that’s why they are called fail-safe iterators. Iterator on CopyOnWriteArrayList, ConcurrentHashMap classes are examples of fail-safe Iterator.

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 are fail-fast and fail-safe iterator?

The Java Collection supports two types of iterators; Fail Fast and Fail Safe. These iterators are very useful in exception handling. The Fail fast iterator aborts the operation as soon it exposes failures and stops the entire operation. Comparatively, Fail Safe iterator doesn’t abort the operation in case of a failure.

What is fail-fast behavior?

When a problem occurs, a fail-fast system fails immediately. In Java, we can find this behavior with iterators. Incase, you have called iterator on a collection object, and another thread tries to modify the collection object, then concurrent modification exception will be thrown. This is called fail-fast.

How ConcurrentHashMap is fail-safe?

concurrent package such as ConcurrentHashMap, CopyOnWriteArrayList, etc. are Fail-Safe in nature. In the code snippet above, we’re using Fail-Safe Iterator. Hence, even though a new element is added to the Collection during the iteration, it doesn’t throw an exception.

What is difference between HashMap and ConcurrentHashMap?

HashMap is non-Synchronized in nature i.e. HashMap is not Thread-safe whereas ConcurrentHashMap is Thread-safe in nature. HashMap performance is relatively high because it is non-synchronized in nature and any number of threads can perform simultaneously.

Does Chrome actually use more RAM?

How Does Google Chrome Manage RAM? Browsers like Chrome manage RAM this way to offer better stability and faster speeds. But Chrome still uses a lot of RAM. If every tab and extension was run in the same process, you might have to restart the whole browser instead of a single tab.

Which is faster HashMap or ConcurrentHashMap?

If you choose a single thread access use HashMap , it is simply faster. For add method it is even as much as 3x more efficient. Only get is faster on ConcurrentHashMap , but not much. When operating on ConcurrentHashMap with many threads it is similarly effective to operating on separate HashMaps for each thread.

Which is an example of a Fail Fast Iterator?

Iterator on ArrayList, HashMap classes are some examples of fail-fast Iterator. Fail-Safe iterators don’t throw any exceptions if a collection is structurally modified while iterating over it.

When to throw ConcurrentModificationException in Fail Fast Iterator?

The Fail-Fast iterator will throw ConcurrentModificationException whenever we modify the collection during iteration. On the other hand, Fail-Safe iterator will not throw ConcurrentModificationException even when we modify the collection during iteration.

Why are iterators called Fail Safe in Java?

Fail-Safe iterators don’t throw any exceptions if a collection is structurally modified while iterating over it. This is because, they operate on the clone of the collection, not on the original collection and that’s why they are called fail-safe iterators.

Can a listiterator be a Fail Fast Iterator?

However, Enumerations do not provide a fail-fast method. On the other hand, the more modern Iterator returned by a Vector’s iterator () and listIterator () methods are fail-fast. Hence, iterators are recommended over enumerations for iterating over the elements of the older container types.

Why iterator is fail-fast? Iterator on ArrayList, HashMap classes are some examples of fail-fast Iterator. This is because, they operate on the clone of the collection, not on the original collection and that’s why they are called fail-safe iterators. Iterator on CopyOnWriteArrayList, ConcurrentHashMap classes are examples of fail-safe Iterator. Is list iterator fail-fast? The iterators…