Java Utililty Methods List to Array

List of utility methods to do List to Array

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Description

The list of methods to do List to Array are organized into topic(s).

Method

Double[]toArray(List values)
to Array 
return values.toArray(new Double[values.size()]);
String[]toArray(List enums)
Converts a list of enumerations to an array of their Enum#toString() representation 
String[] out = new String[enums.size()];
for (int i = 0; i < out.length; i++) {
    out[i] = enums.get(i).toString();
return out;
int[]toArray(List from, int[] to)
Copy the given List to the specified Array at offset zero. 
if (to == null || to.length < from.size()) {
    to = new int[from.size()];
int i = 0;
for (Integer element : from) {
    to[i++] = element;
return to;
...
int[]toArray(List l)
Returns the non-null integers in the given list as an array. 
if (l == null) {
    return null;
int count = 0;
for (Integer e : l) {
    if (e != null) {
        count++;
int[] result = new int[count];
int i = 0;
for (Integer e : l) {
    if (e != null) {
        result[i++] = e;
return result;
int[]toArray(List list)
to Array 
int[] ret = new int[list.size()];
int i = 0;
for (Integer e : list) {
    ret[i++] = e.intValue();
return ret;
int[]toArray(List list)
Converts a list of integers to an array 
int[] array = new int[list.size()];
for (int i = 0, l = list.size(); i < l; i++)
    array[i] = list.get(i);
return array;
int[]toArray(List list)
to Array 
int[] result = new int[list.size()];
int index = 0;
for (Integer number : list) {
    result[index++] = number;
return result;
ListtoLongList(String str, String splitStr)
to Long List 
if (str != null) {
    ArrayList<Long> longList = new ArrayList<Long>();
    String[] strList = str.split(splitStr);
    for (String string : strList) {
        longList.add(Long.parseLong(string));
    return longList;
return null;
ListtoLongList(String[] array)
Converts a String array to a long array. 
List<Long> out = new ArrayList<Long>(array.length);
for (int i = 0; i < array.length; i++) {
    if (array[i] == null)
        throw new RuntimeException("Null value in position " + i);
    out.add(Long.parseLong(array[i]));
return out;
Object[]toObjectArray(List> lists)
to Object Array 
List<String[]> output = new ArrayList<>();
for (List<String> l : lists) {
    output.add(l.toArray(new String[0]));
return output.toArray();