Performance: Iterating through a List in Java

Question

Is it slower to iterate through a list in Java like this:

for (int i=0;i

as opposed to:

Answer 1

THERE CAN BE A DIFFERENCE.

If a List implementation also implements java.util.RandomAccess (like ArrayList does), then it is just about faster to use its get() method over an interator.

If it does not implement java.util.RandomAccess (for example, LinkedList does not), then it is substantially faster to use an iterator.

However, this only matter if you are using lists containing thousands of (possibly scattered) objects or that are constantly traversed (as if performing copious amounts of math on List objects representing numerical vectors.)