Java tutorial
//package com.java2s; import java.util.ArrayList; import java.util.Collection; import java.util.Iterator; import java.util.List; public class Main { public static int[] toIntArray(String[] ss) { int[] r = new int[ss.length]; for (int i = 0; i < r.length; i++) { r[i] = Integer.valueOf(ss[i]); } return r; } public static int[] toIntArray(List<Integer> list) { return toPrimitive(list.toArray(new Integer[0])); } public static int[] toPrimitive(Integer[] array) { int[] r = new int[array.length]; for (int i = 0; i < array.length; i++) { r[i] = array[i]; } return r; } public static long[] toArray(Iterator<Long> it) { List<Long> list = toList(it); return toArray(list); } public static long[] toArray(Collection<Long> collection) { long[] array = new long[collection.size()]; Iterator<Long> it = collection.iterator(); int i = 0; while (it.hasNext()) { array[i++] = it.next(); } return array; } public static List<Long> toList(Iterator<Long> it) { List<Long> list = new ArrayList<Long>(); while (it.hasNext()) { list.add(it.next()); } return list; } }