Java Utililty Methods List Union

return shallowUnion(new ArrayList<>(values).toArray(new List[] {}));

StringBuilder sb = new StringBuilder();
for (char[] characters : list) {
    for (int i = 0; i < list.length; i++) {
        if (!contains(sb, characters[i])) {
            sb.append(list[i]);
char[] toReturn = new char[sb.length()];
sb.getChars(0, sb.length(), toReturn, 0);
Arrays.sort(toReturn);
return toReturn;

final ArrayList result = new ArrayList(list1);
result.addAll(list2);
return result;

final ArrayList result = new ArrayList(list1);
result.addAll(list2);
return result;

final List<E> result = new ArrayList<E>(list1.size() + list2.size());
result.addAll(list1);
result.addAll(list2);
return result;

if (list1 == null || list2 == null)
    throw new NullPointerException("Not initizalized lists");
List<E> concat = new ArrayList<E>(list1.size() + list2.size());
concat.addAll(list1);
E item;
ListIterator<E> iter = list1.listIterator();
while (iter.hasNext()) {
    item = iter.next();
...

final List<T> union = new ArrayList<>();
for (List<T> list : lists) {
    union.addAll(list);
return union;

if (A == null)
    return B;
if (B == null)
    return A;
List list = new ArrayList(A);
for (Iterator i = B.iterator(); i.hasNext();) {
    Object o = i.next();
    if (!list.contains(o))
...

List list = new ArrayList(Arrays.asList(new Object[ls.size()]));
Collections.copy(list, ls);
list.addAll(ls2);
return list;

int size = 0;
for (byte[] bs : byteList) {
    size += bs.length;
byte[] ret = new byte[size];
int pos = 0;
for (byte[] bs : byteList) {
    System.arraycopy(bs, 0, ret, pos, bs.length);
...