请大家帮忙看看这段求数列组合的递归代码，多谢

import java.util.Arrays;import java.util.LinkedList;import java.util.List;public class Test {    public static void main(String[] args) {             String[] array=new String[]{               "1","2","3","4"       };       listAll(Arrays.asList(array),"");    }    public static void listAll(List candidate,String prefix){        System.out.println(prefix);        for(int i=0;i<candidate.size();i++){            List temp = new LinkedList(candidate);            listAll(temp,prefix+temp.remove(i));        }    }}

for(int i=0;i<candidate.size();i++){            List temp = new LinkedList(candidate);            listAll(temp,prefix+temp.remove(i));        }