LinkedList
might allocate fewer entries, but those entries are astronomically more expensive than they’d be for ArrayList
— enough that even the worst-case ArrayList
is cheaper as far as memory is concerned.
(FYI, I think you’ve got it wrong; ArrayList
grows by 1.5x when it’s full, not 2x.)
See e.g. https://github.com/DimitrisAndreou/memory-measurer/blob/master/ElementCostInDataStructures.txt : LinkedList
consumes 24 bytes per element, while ArrayList
consumes in the best case 4 bytes per element, and in the worst case 6 bytes per element. (Results may vary depending on 32-bit versus 64-bit JVMs, and compressed object pointer options, but in those comparisons LinkedList
costs at least 36 bytes/element, and ArrayList
is at best 8 and at worst 12.)
UPDATE:
I understand from other posts here that individual elements stored in a LinkedList takes more space than an ArrayList as LinkedList also needs to store the node information, but I am still guessing for the scenario I have defined LinkedList might be a better option. Also, I do not want to get into the performance aspect (fetching, deleting etc) , as much has already been discussed on it.
To be clear, even in the worst case, ArrayList
is 4x smaller than a LinkedList
with the same elements. The only possible way to make LinkedList
win is to deliberately fix the comparison by calling ensureCapacity
with a deliberately inflated value, or to remove lots of values from the ArrayList
after they’ve been added.
In short, it’s basically impossible to make LinkedList
win the memory comparison, and if you care about space, then calling trimToSize()
on the ArrayList
will instantly make ArrayList
win again by a huge margin. Seriously. ArrayList
wins.