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

Check out the list of datastructures here. Pick one depending on your requirements. Like Guarev mentioned, a HashMap is probably your best bet. Hashmaps have the advantage of a constant time for insert, search, and delete.

ArrayLists are not a good structure for a storing a lot of data, as the memory usage quickly goes through the roof, and search/delete times get very expensive very quickly.