Java Utililty Methods List Difference

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

if (doublesA.size() != doublesB.size()) {
    throw new IllegalArgumentException("The two lists must be of same size!");
List<Double> diff = new ArrayList<Double>(doublesA.size());
for (int i = 0; i < doublesA.size(); i++) {
    diff.add(doublesA.get(i) - doublesB.get(i));
return diff;
...

Set<T> diff = new HashSet<>();
for (T t : list1) {
    if (!list2.contains(t)) {
        diff.add(t);
return diff;

final List<Double> result = new ArrayList<Double>();
for (int i = 0; i < minuend.size(); ++i) {
    final Object o1 = minuend.get(i);
    final Object o2 = subtrahend.get(i);
    if (areBothNumbers(o1, o2)) {
        subtract(result, o1, o2);
    } else {
        result.add(Double.NaN);
...

final List<T> result = new ArrayList<T>(list1);
final Iterator<? extends T> iterator = list2.iterator();
while (iterator.hasNext()) {
    result.remove(iterator.next());
return result;

HashSet<String> set = new HashSet<String>();
HashSet<String> set1 = new HashSet<String>(Arrays.asList(list1));
HashSet<String> set2 = new HashSet<String>(Arrays.asList(list2));
for (final String s : list1) {
    if (!set2.contains(s)) {
        set.add(s);
for (final String s : list2) {
    if (!set1.contains(s)) {
        set.add(s);
return set.toArray(new String[set.size()]);

List<E> results = create();
if (firstList != null)
    results.addAll(firstList);
if (secondList != null)
    results.removeAll(secondList);
return results;

for (T1 elem : lst2) {
    lst1.remove(elem);

List<T> diff = new ArrayList<T>(set1);
diff.removeAll(set2);
return diff;

List<E> result = new ArrayList<>();
for (E i : a) {
    if (b.contains(i))
        continue;
    result.add(i);
return result;