java - Permutation of an ArrayList of numbers using recursion -

i trying learn recursion creating permutation of arraylist:

 {1,2,3} 

but concept of recursive calls keeps going on head. know how iterative solution. there systematic way convert iterative solution recursive?

private static arraylist<arraylist<integer>> permutate(arraylist<integer> list) {     arraylist<arraylist<integer>> result = new arraylist<arraylist<integer>>();      result.add(new arraylist<integer>());      (int = 0; < list.size(); i++) {         arraylist<arraylist<integer>> current = new arraylist<arraylist<integer>>();          (arraylist<integer> l : result) {             (int j = 0; j < l.size()+1; j++) {                 l.add(j, list.get(i));                  arraylist<integer> temp = new arraylist<integer>(l);                 current.add(temp);                  l.remove(j);             }         }          result = new arraylist<arraylist<integer>>(current);     }      return result;  } 

public static list<list<integer>> listpermutations(list<integer> list) {      if (list.size() == 0) {         list<list<integer>> result = new arraylist<list<integer>>();         result.add(new arraylist<integer>());         return result;     }      list<list<integer>> returnme = new arraylist<list<integer>>();      integer firstelement = list.remove(0);      list<list<integer>> recursivereturn = listpermutations(list);     (list<integer> li : recursivereturn) {          (int index = 0; index <= li.size(); index++) {             list<integer> temp = new arraylist<integer>(li);             temp.add(index, firstelement);             returnme.add(temp);         }      }     return returnme; } 

to test used:

public static void main(string[] args) throws exception {      list<integer> intlist = new arraylist<integer>();     intlist.add(1);     intlist.add(2);     intlist.add(3);     list<list<integer>> mylists = listpermutations(intlist);      (list<integer> al : mylists) {         string appender = "";         (integer : al) {             system.out.print(appender + i);             appender = " ";         }         system.out.println();     }  } 

which gave me output:

1 2 3 2 1 3 2 3 1 1 3 2 3 1 2 3 2 1