Here you can find the source of setBit(byte[] arr, int bit)
public static void setBit(byte[] arr, int bit)
//package com.java2s; /*/* w w w . j av a 2 s. c om*/ * The MIT License * * Created by Jarrod Boyes on 24/03/14. * Copyright (c) 2014 LIFX Labs. All rights reserved. * * 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. */ public class Main { public static void setBit(byte[] arr, int bit) { int index = bit / 8; // Get the index of the array for the byte with this bit int bitPosition = bit % 8; // Position of this bit in a byte arr[index] = (byte) (arr[index] | (1 << bitPosition)); } }