Java Utililty Methods List to Primitive Array

double[] primitiveArray = new double[array.size()];
for (int i = 0; i < array.size(); ++i) {
    primitiveArray[i] = array.get(i).doubleValue();
return primitiveArray;

double[] output = new double[input.size()];
for (int i = 0; i < input.size(); i++) {
    output[i] = input.get(i);
return output;

double[] arr = new double[list.size()];
for (int i = 0; i < list.size(); i++)
    arr[i] = list.get(i);
return arr;

if (target_ == null)
    return null;
int[] array = new int[target_.size()];
for (int i = 0; i < array.length; i++)
    array[i] = target_.get(i).intValue();
return array;

int nullcounter = 0;
for (Long l : list) {
    if (l == null) {
        nullcounter++;
long[] result = new long[list.size() - nullcounter];
nullcounter = 0;
...

double[] result = new double[values.size()];
Iterator<Double> iterator = values.iterator();
for (int i = 0; i < result.length; i++) {
    result[i] = iterator.next().doubleValue();
return result;

int nItems = temp.size();
if (nItems < 1) {
    return null;
Integer[] boxInts = new Integer[nItems];
temp.toArray(boxInts);
int[] result = new int[nItems];
for (int i = 0; i < result.length; i++) {
...

int[] array = new int[values.size()];
int cursor = 0;
for (Object o : values) {
    array[cursor] = (Integer) o;
    cursor++;
return array;

int[] result = new int[listOfInt.size()];
int i = 0;
for (Integer n : listOfInt) {
    result[i++] = n;
return result;

final long[] res = new long[items.size()];
for (int i = 0; i < res.length; i++)
    res[i] = items.get(i);
return res;