Here you can find the source of currentTimeMillis()
public static long currentTimeMillis()
//package com.java2s; //License from project: LGPL public class Main { private static int timeZoneOffset = 0; public static long currentTimeMillis(boolean timezone) { if (timezone) return System.currentTimeMillis() + (long) timeZoneOffset; else//from w ww .j a v a 2s . c om return System.currentTimeMillis(); } public static long currentTimeMillis() { return System.currentTimeMillis() + (long) timeZoneOffset; } public static long currentTimeMillis(long time) { return time + (long) timeZoneOffset; } }