What is the difference between CopyOnWriteArrayList and ArrayList?

What is the difference between CopyOnWriteArrayList and ArrayList?

CopyOnWriteArrayList is a thread-safe variant of ArrayList. It creates a new copy of the list on each write operation, making it suitable for scenarios where reads are more frequent than writes.

When should I use CopyOnWriteArrayList instead of ArrayList?

You should use CopyOnWriteArrayList when you have a high read-to-write ratio and need to ensure thread safety without external synchronization.

Are there any performance drawbacks to using CopyOnWriteArrayList?

Yes, the main drawback is that it can be less efficient for write operations since it creates a new copy of the list each time an element is added or removed.

Can you give an example of when to use each?

Use ArrayList for single-threaded applications or when writes are frequent. Use CopyOnWriteArrayList in concurrent scenarios where reads are dominant.