CopyOnWriteArrayList

CopyOnWriteArrayList is a thread-safe variant of ArrayList in Java. It provides a way to safely modify the list while iterating over it, without worrying about ConcurrentModificationException.

When an element is added, modified, or removed from CopyOnWriteArrayList, a new copy of the underlying array is created with the new element(s) and the reference to the new array is updated. This ensures that the original array is not modified, and any ongoing iterations over the list continue to work on the old copy of the array.

CopyOnWriteArrayList is useful in scenarios where reads outnumber writes, and the list needs to be thread-safe. However, it can be memory intensive and slow for large lists or frequent modifications. It is also not suitable for scenarios where the data needs to be updated in real-time or with low latency.