Java tutorial
//package com.java2s; import java.util.Random; public class Main { private static String randomABC(int n) { String chars = "abcde0123456789"; String res = ""; Random rnd = new Random(); int leng = chars.length(); for (int i = 0; i < n; i++) { res = res + chars.charAt(rnd.nextInt(leng)); } return res; } }