Default collection implementation

Question

If I am not mistaken default implementation for collection in Kodo is
LinkedList based
below is some statistics on collection performance (populating and iterating
collections)
the same test against 3 collections implementations (JDK 1.4.1)
Not only ArrayList by far the fastest and memory friendly it also garbage
collected much sooner and better -
I show here max memory consumption and last to would not be garbage
collected till all memory is in use (old generation GC)
and ArrayList seems to be collected by young gen GC because it was collected
very quickly between test cycles why other only when all memory was used
So please make ArrayList your default collection implementation :-)
Small collection size (40)
time(ms) memory(kb)
ArrayList 5,218 62,154
LinkedList 14,125 240,066
HashSet 27,000 311,825
the same but using using random inserts - append(index, object) rather than
append(object):
ArrayList 8937, 53591
LinkedList 15047, 240066
Larger collection size (200)
ArrayList 4860, 47709
LinkedList 18468, 290704
HashSet 34391, 422282
the same but using using random inserts - append(index, object) rather than
append(object):
ArrayList 11844, 47709
LinkedList 25766, 290704

Answer 1

Here is my quick and dirty perf test:
private static void perfTest() {
Integer v[] = new Integer[200];
for (int i = 0; i < v.length; i++) {
v[i] = new Integer(i);
Collection c[] = new Collection[10000];
long time = System.currentTimeMillis();
maxMem = 0;
for (int k = 0; k < 6; k++) {
for (int i = 0; i < c.length; i++) {
if (i % 2000 == 0) {
System.out.println(System.currentTimeMillis() - time + ", " +
maxMem());
//List l = new ArrayList();
//List l = new LinkedList();
//c[i] = l;
c[i] = new HashSet();
Collection co = c;
for (int j = 0; j < v.length; j++) {
co.add(v[j]);
//l.add(j/2, v[j]);
for (int i = 0; i < c.length; i++) {
if (i % 2000 == 0) {
System.out.println(System.currentTimeMillis() - time + ", " +
maxMem());
for (Iterator iterator = c[i].iterator(); iterator.hasNext();) {
iterator.next();
private static long maxMem = 0;
private static long maxMem() {
long mem = (Runtime.getRuntime().totalMemory() -
Runtime.getRuntime().freeMemory()) / 1000;
return mem;
// maxMem = Math.max(mem, maxMem);
// return maxMem;
"Abe White" <[email protected]> wrote in message
news:[email protected]..
Interesting. We'll certainly consider switching the default.