Fast algorithm to remove a number of elements from an ArrayList

Question

Say an ArrayList is of size n.

In my case, I often need to remove from 1 to n elements with different indexes from an ArrayList.

By using visualvm profiler,

Answer 1

ArrayList is not really a good data structure to do this operation.

I would suggest you to use the HashMap for this purpose, you can keep the key, value pair with the key as the indexes.