Generate All Permutations of a String

Suppose we are given a String and asked to find all the permutations of that String.

So for abcd it will be like:

bdAc

bdcA

cAbd

cAdb

cbAd

cbdA

cdAb

cdbA

dAbc

dAcb

dbAc

dbcA

dcAb

dcbA

The Java code should be the following:

public class StringPermutation {

    

    public static void main(String args[]){

        String perm = "Abcd";

        System.out.println(permutation("",perm));

    }

    public static String permutation(String prefix, String perm){

        if(perm.length() == 0){

            System.out.println(prefix);

 } else{

               for (int i = 0; i < perm.length(); i++){

                   permutation(prefix + perm.charAt(i), perm.substring(0,i) 

                      + perm.substring(i+1));

               }

}

        return prefix;

    }

}