Java program to print all the permutations of a string ...

here  is the code 

       
 import java.io.*;
 import java.util.*;
 class permute_string {
  public static ArrayList < String > getPerms(String s) {
   ArrayList < String > permutations = new ArrayList < String > ();
   if (s == null) { // error case
    return null;
   } else if (s.length() == 0) {
    permutations.add("");
    return permutations;
   }

   char first = s.charAt(0); // get the first character
   String remainder = s.substring(1); // remove the first character
   ArrayList < String > words = getPerms(remainder);
   for (String word: words) {
    for (int j = 0; j <= word.length(); j++) {
     permutations.add(insertCharAt(word, first, j));
    }
   }
   return permutations;
  }

  public static String insertCharAt(String word, char c, int i) {
   String start = word.substring(0, i);
   String end = word.substring(i);
   return start + c + end;
  }


  public static void main(String args[]) {


   System.out.println(getPerms(args[0]));
  }
 }