Here you can find the source of maxValue(int bits)
public static long maxValue(int bits)
//package com.java2s; /*//from w ww . j ava2s .c o m * Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code 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. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ public class Main { /** * Get the maximum value representable in a {@code bits} bit signed integer. */ public static long maxValue(int bits) { assert 0 < bits && bits <= 64; return mask(bits - 1); } /** * Get a bitmask with the low {@code bits} bit set and the high {@code 64 - bits} bit clear. */ public static long mask(int bits) { assert 0 <= bits && bits <= 64; if (bits == 64) { return 0xffffffffffffffffL; } else { return (1L << bits) - 1; } } }