Java Utililty Methods List Permutate

List<List<E>> result = new ArrayList<List<E>>();
if (list1 != null) {
    int s1 = list1.size();
    if (s1 > 0) {
        int index = 0;
        for (Iterator<E> it = list1.iterator(); it.hasNext(); ++index) {
            E elt = it.next();
            List<E> list2 = new LinkedList<E>(list1.subList(0, index));
...

for (int i = index; i < list.size(); i++) {
    Collections.swap(list, i, index);
    permute(list, index + 1, result);
    Collections.swap(list, index, i);
if (index == list.size() - 1) {
    result.add(new ArrayList<T>(list));

T[] arr_new = arr.clone();
for (int i = 0; i < arr.length; i++) {
    arr_new[p.get(i)] = arr[i];
return arr_new;

List<List<List<E>>> result = new ArrayList<List<List<E>>>();
if (elementLists == null || elementLists.size() == 0) {
    return result;
int size = elementLists.size();
if (size == 1) {
    List<E> elements = elementLists.get(0);
    List<List<E>> groups = new ArrayList<List<E>>();
...

if (permutations.length != list.size()) {
    throw new IllegalArgumentException("List length and permutation length are not equal");
List<Object> tmpList = new ArrayList<Object>(permutations.length);
for (int i = 0; i < permutations.length; i++) {
    tmpList.add(list.get(permutations[i]));
list.clear();
...

List<T> result = new ArrayList<T>();
result.addAll(in);
Random R = new Random(seed);
for (int permuteSize = in.size(); permuteSize > 1; permuteSize--) {
    int pos = Math.abs(R.nextInt()) % permuteSize;
    T tmp = result.get(permuteSize - 1);
    result.set(permuteSize - 1, result.get(pos));
    result.set(pos, tmp);
...

List<T> output = new ArrayList<T>();
for (int i = 0; i < permutation.length; i++) {
    output.add(list.get(permutation[i]));
return output;

permLevel = permLevel + 1;
value[k] = permLevel;
if (permLevel == n) {
    res.add(copySubarray(value, 0, value.length));
} else {
    for (int i = 0; i < n; i++) {
        if (value[i] == 0)
            permVisit(value, n, i, res);
...