Here you can find the source of convert(BitSet bits)
public static long convert(BitSet bits)
//package com.java2s; //License from project: Open Source License import java.util.BitSet; public class Main { public static BitSet convert(long value) { BitSet bits = new BitSet(); int index = 0; while (value != 0L) { if (value % 2L != 0) { bits.set(index);/*from w w w.j a v a 2 s . c om*/ } ++index; value = value >>> 1; } return bits; } public static long convert(BitSet bits) { long value = 0L; for (int i = 0; i < bits.length(); ++i) { value += bits.get(i) ? (1L << i) : 0L; } return value; } }