Question

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

for (int i=0;i<list.size();i++) {
    .. list.get(i)
}

as opposed to:

for (Object o: list) {
    ... o
}

Answer 1

I assume you ask out of pure curiosity
and won’t cite Knuth (somebody
probably will).

I believe that once your code gets compiled, it doesn’t make a difference. It does make a difference before (example 2 is a lot more readable and concise), so go for number 2 and do not care about the rest.

Just my 2 cents

EDIT

Note your code in snippet number 1 calculates list.size() every time the loop runs, that could make it even slower than number 2

YET ANOTHER EDIT

Something I had to double check, Joshua Bloch recommends using for each loops (see item 46 of Effective Java). I believe that ends all kinds of discussions. Thanks Josh! 🙂