Java Utililty Methods Collection to Array

List of utility methods to do Collection to Array

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Collection to Array

Description

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

Method

Object[] asArray(Collection c)
Returns an array with the elements in a given collection.

Object[] array = new Object[c.size()];
int i = 0;
for (Iterator it = c.iterator(); it.hasNext();) {
 array[i++] = it.next();
return array;

E[] asArray(Collection collection, E[] a)
as Array

return asList(collection).toArray(a);

boolean[] asBooleanArray(Collection collection)
as Boolean Array

boolean[] array = new boolean[collection.size()];
Iterator<Boolean> iterator = collection.iterator();
int i = 0;
while (iterator.hasNext()) {
 array[i++] = iterator.next();
return array;

long[] asLongArray(final Collection ls)
as Long Array

final long[] d = new long[ls.size()];
int i = 0;
for (final Number num : ls)
 d[i++] = num.longValue();
return d;

long[] asLongArray(java.util.Collection c)
Returns 'c' as a long array.

int i = 0, n = (c == null) ? 0 : c.size();
long[] ans = new long[n];
if (n > 0)
 for (Number nr : c)
 ans[i++] = nr.longValue();
return ans;

Object[] collectionToArray(Collection collection)
collection To Array

Object[] objs = null;
if (isNotEmpty(collection)) {
 objs = new Object[collection.size()];
 collection.toArray(objs);
return objs;

int[] collectionToIntArray(Collection c)
collection To Int Array

int[] toReturn = new int[c.size()];
Iterator<Integer> it = c.iterator();
for (int i = 0; i < toReturn.length; i++) {
 toReturn[i] = it.next().intValue();
return toReturn;

int[] collectionToIntArray(final Collection numbers)
collection To Int Array

final int[] ret = new int[numbers.size()];
int i = 0;
for (Number n : numbers) {
 ret[i++] = n.intValue();
return ret;

Object[] collectionToObjectArray(Collection c)
Convenience method for converting a collection to an Object[]

if (c == null)
 return new Object[0];
return c.toArray(new Object[c.size()]);

CharSequence collectionToObjectArray(final Collection _list)
collection To Object Array

final StringBuilder ret = new StringBuilder();
if (!_list.isEmpty()) {
 boolean first = true;
 ret.append("[");
 for (final CharSequence entry : _list) {
 if (first) {
 first = false;
 } else {
...