Execution Speeds of Java Collections

Execution Speeds of Java Collections - List/for, Array/for, List/foreach, Array/foreach

===Results==

List/for 3697

Array/for 1548

List/foreach 5654

Array/foreach 5659

===Code====

List list = new ArrayList(); Integer[] arr = new Integer[6000000]; Random rand = new Random(12345); for (int i = 0; i < 6000000; i++) { list.add(rand.nextInt(5000)); arr[i] = rand.nextInt(); } int chk = 0; Stopwatch watch = new Stopwatch(); watch.start(); for (int rpt = 0; rpt < 100; rpt++) { int len = list.size(); for (int i = 0; i < len; i++) { chk += list.get(i); } } watch.stop(); System.out.println("List/for: " + watch.elapsedMillis()); chk = 0; watch = watch.reset(); watch = watch.start(); for (int rpt = 0; rpt < 100; rpt++) { for (int i = 0; i < arr.length; i++) { chk += arr[i]; } } watch.stop(); System.out.println("Array/for: "+ watch.elapsedMillis()); chk = 0; watch = watch.reset(); watch = watch.start(); for (int rpt = 0; rpt < 100; rpt++) { for(Integer i: list) { chk += i; } } watch.stop(); System.out.println("List/foreach: " + watch.elapsedMillis()); chk = 0; watch = watch.reset(); watch = watch.start(); for (int rpt = 0; rpt < 100; rpt++) { for(Integer i: list) { chk += i; } } watch.stop(); System.out.println("Array/foreach: " + watch.elapsedMillis());