Here you can find the source of shuffle(int[] input)
public static int[] shuffle(int[] input)
//package com.java2s; /*/*w w w . jav a2 s . co m*/ * Copyright 2008-2009 LinkedIn, Inc * Copyright (c) 2013 Big Switch Networks, Inc. * * Licensed under the Apache License, Version 2.0 (the "License"); you may not * use this file except in compliance with the License. You may obtain a copy of * the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the * License for the specific language governing permissions and limitations under * the License. */ import java.util.ArrayList; import java.util.Collections; import java.util.List; import java.util.Random; public class Main { public static final Random SEEDED_RANDOM = new Random(19873482374L); /** * Weirdly java doesn't seem to have Arrays.shuffle(), this terrible hack * does that. * * @return A shuffled copy of the input */ public static int[] shuffle(int[] input) { List<Integer> vals = new ArrayList<Integer>(input.length); for (int i = 0; i < input.length; i++) vals.add(input[i]); Collections.shuffle(vals, SEEDED_RANDOM); int[] copy = new int[input.length]; for (int i = 0; i < input.length; i++) copy[i] = vals.get(i); return copy; } }