Here you can find the source of getDSTTime(TimeZone tz, Date date)
public static long getDSTTime(TimeZone tz, Date date)
//package com.java2s; import java.util.*; public class Main { public static long getDSTTime(TimeZone tz, Date date) { return date.getTime() + (tz.inDaylightTime(date) ? tz.getDSTSavings() : 0); }//from ww w. j a va2 s . c om }