Here you can find the source of readLong(InputStream is)
public static long readLong(InputStream is) throws IOException
//package com.java2s; /*/* ww w .j av a 2s .c o m*/ * Copyright (c) 1998-2015 Caucho Technology -- all rights reserved * * This file is part of Baratine(TM)(TM) * * Each copy or derived work must preserve the copyright notice and this * notice unmodified. * * Baratine is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * Baratine is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE, or any warranty * of NON-INFRINGEMENT. See the GNU General Public License for more * details. * * You should have received a copy of the GNU General Public License * along with Baratine; if not, write to the * * Free Software Foundation, Inc. * 59 Temple Place, Suite 330 * Boston, MA 02111-1307 USA * * @author Scott Ferguson */ import java.io.IOException; import java.io.InputStream; public class Main { public static long readLong(InputStream is) throws IOException { return (((long) is.read() << 56) + ((long) is.read() << 48) + ((long) is.read() << 40) + ((long) is.read() << 32) + ((long) is.read() << 24) + ((long) is.read() << 16) + ((long) is.read() << 8) + ((long) is.read())); } }