How to shuffle characters in a string without using Collections.shuffle(…)?

Question

How do I shuffle the characters in a string (e.g. hello could be ehlol or lleoh or ...). I don\'t want to use the Collections.shuffle(...) method, is there anyt

Answer 1

Without external libraries, for those who do not mind using Collections.shuffle():

static String shuffle(String string){

    List<Character> list = string.chars().mapToObj(c -> new Character((char) c))
                                         .collect(Collectors.toList());
    Collections.shuffle(list);
    StringBuilder sb = new StringBuilder();
    list.forEach(c -> sb.append(c));

    return sb.toString();
}

Answer 2

import java.util.Random;

public class carteRecharge {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        String characters = "AZERTYUIOPQSDFGHJKLMWXCVBNazertyuiopqsdfghjklmwxcvbn1234567890";

        Random rand = new Random();

        //Nombre de caratère à tirer 
        int length = 20;

        //La variable qui contiendra le mot tire
        String randomString = "";

        //
        char[] text = new char[length];

        for(int i = 0; i < length; i++) {
            text[i] = characters.charAt(rand.nextInt(characters.length()));

        }


        for(int i=0; i<text.length; i++) {
            randomString += text[i];
        }

        System.out.print(randomString);


    }

}