Java tutorial
//package com.java2s; import java.util.Random; public class Main { public static String getRandom(int len, String[] arr) { String s = ""; if (0 < len && null != arr && arr.length >= 0) { Random ra = new Random(); int arrLen = arr.length; for (int i = 0; i < len; i++) { s += arr[ra.nextInt(arrLen)]; } return s; } else { return s; } } }