What is the memory usage of CopyOnWriteArrayList?

What is the memory usage of CopyOnWriteArrayList compared to ArrayList?

CopyOnWriteArrayList uses more memory than ArrayList because it creates a new copy of the array on each modification.

Why does it create a new copy? Is it for thread safety?

Yes, it creates a new copy to ensure thread safety. This allows multiple threads to read without locking.

Does this mean it has a performance overhead?

Yes, the overhead comes from copying the array, which can be costly in terms of memory and time during writes.

When should I use CopyOnWriteArrayList instead of ArrayList?

Use CopyOnWriteArrayList when you have more reads than writes, especially in a concurrent environment.