Why do so many code samples here use Arrays?

Question

I've seen many code samples here use Arrays. Why? I much prefer to use ArrayLists, and Vectors if I need synchronization or HashSets if I require uniqueness. I don't understand why people are using Arrays when the Collection classes are so useful. You can change the underlying datastructure without changing any of the access code.

Answer 1

I guess they are faster...
public class Test1 {
     public static void main(String[] args) {
            Integer zero = new Integer(0);
               long start = System.currentTimeMillis();
               for (int j = 0; j < 1000; j++) {
                    Integer[] array = new Integer[10000];
                    for (int i = 0; i < 10000; i++) {
                         array[i] = zero;
               long finish = System.currentTimeMillis();
               System.out.println(finish - start);
               start = System.currentTimeMillis();
               for (int j = 0; j < 1000; j++) {
                    ArrayList arrayList = new ArrayList();
                    for (int i = 0; i < 10000; i++) {
                         arrayList.add(zero);
               finish = System.currentTimeMillis();
               System.out.println(finish - start);
}~460 ms for array
~1600 for ArrayList
Still, the benefit of the Collections interface and the better OO design of code that uses these classes is probably worth it in most cases, IMO.