Here you can find the source of bitCount(final Integer i)
private static int bitCount(final Integer i)
//package com.java2s; // Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file public class Main { private static int bitCount(final Integer i) { return Integer.bitCount(i); }//from w w w . j av a 2s . c o m }