Here you can find the source of shuffle(List> list)
public static void shuffle(List<?> list)
//package com.java2s; //License from project: Apache License import java.util.Collections; import java.util.List; import java.util.Random; public class Main { public static void shuffle(List<?> list) { Collections.shuffle(list); }// ww w . j a v a 2 s. c o m public static void shuffle(List<?> list, Random rnd) { Collections.shuffle(list, rnd); } }