Fastest way to get the first n elements of a List into an Array

Question

What is the fastest way to get the first n elements of a list stored in an array?

Considering this as the scenario:

int n = 10;
ArrayList

        

Answer 1

Option 3

Iterators are faster than using the get operation, since the get operation has to start from the beginning if it has to do some traversal. It probably wouldn't make a difference in an ArrayList, but other data structures could see a noticeable speed difference. This is also compatible with things that aren't lists, like sets.

String[] out = new String[n];
Iterator iterator = in.iterator();
for (int i = 0; i < n && iterator.hasNext(); i++)
    out[i] = iterator.next();