Here you can find the source of getRandomInt(int min, int max)
public static int getRandomInt(int min, int max)
//package com.java2s; /* Copyright (C) 2000-2003 The Software Conservancy as Trustee. * All rights reserved./* ww w . ja v a 2 s . co m*/ * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to * deal in the Software without restriction, including without limitation the * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or * sell copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS * IN THE SOFTWARE. * * Nothing in this notice shall be deemed to grant any rights to trademarks, * copyrights, patents, trade secrets or any other intellectual property of the * licensor or any contributor except as expressly stated herein. No patent * license is granted separate from the Software, for code that you delete from * the Software, or for combinations of the Software with other software or * hardware. */ import java.util.*; public class Main { private static Random random = new Random(); public static int getRandomInt(int min, int max) { if (min > max) throw new IllegalArgumentException("min > max"); if (min == Integer.MIN_VALUE && max == Integer.MAX_VALUE) { // special case return random.nextInt(); } else { return random.nextInt(max - min + 1) + min; } } }