import java.util.ArrayList;
import java.util.List;

public class TestArrayVsArrayList {
    public static void main(String[] args) {
        int[] array = new int[1000000];
        List<Integer> arrayList = new ArrayList<Integer>(1000000);

        long startTime = System.nanoTime();
        for (int i = 0; i < 1000000; i++) {
            array[i] = i;
        }
        System.out.println("Array takes: " + (System.nanoTime() - startTime) / 1000000000F);

        startTime = System.nanoTime();
        for (int i = 0; i < 1000000; i++) {
            arrayList.add(i);
        }
        System.out.println("ArrayList takes: " + (System.nanoTime() - startTime) / 1000000000F);
    }
}

RESULTS:

Array takes: 0.010048291
ArrayList takes: 0.03267106

Approx: 300% faster to use Array