import java.util.ArrayList;public class test { static ArrayList list = new ArrayList(); public static void main(String[] args) { String[] strs = {"A","B","C","D"}; perm(strs, 0, strs.length); for(String s:list){ System.out.println(s); } list.clear(); } private static void perm(String[] strs,int start,int end){ String s = ""; if(start==end){ for(int i=0;i |