Source code

      Dim tz As TimeZone 
   Dim dst
   Dim calendar = java#util#Calendar.getInstance 
      
   tz = TimeZone.getDefault 
   
   dst = (calendar.get(java#util#Calendar.DST_OFFSET))/1000
   
   Label1.Caption = now & " " & tz.getDisplayName & " " & dst & "s"

Source code

Option Explicit
'http://msdn.microsoft.com/de-de/library/b5xbyt6f(VS.80).aspx

Public Function DateDiff(Interval As String, Date1 As Variant, Date2 As Variant) As Long
   'Gibt die Anzahl der Zeitintervalle zwischen zwei Datumsangaben zurück

   'returns the amount of timespans between the two dates
   'Interval: a string representing the kind of time
   'Date1: one end of the timespan
   'Date2: the other end of the timespan
   
   ' note: does not consider different first days of the week
   DateDiff = DateVal(Interval, Date2) - DateVal(Interval, Date1)
End Function

Private Function DateVal(Interval As String, d As Variant) As Long
   Dim d1 As java#util#Date = d
   Dim sec As Long = CLng(d1.getTime() * 0.001)
   Dim y As Integer = d1.getYear 
   Dim ret As Long
   
   Select Case Interval
   Case "s": ret = sec
   Case "n": ret = CLng(sec / 60.0)
   Case "h": ret = CLng(sec / 3600.0)
   Case "d", "y": ret = CLng(sec / (24 * 3600.0))
   Case "w", "ww": ret = y * 52 + GetWeekShort(d1)  '  quick hack! not correct for multiple-year diffs
   Case "m": ret = 12 * y + d1.getMonth 
   Case "q": ret = 4 * y + d1.getMonth / 4
   Case "yyyy": ret = y
   Case Else
      debug.Print "DateVal: unknown interval '" & Interval & "'"
      ret = 0
   End Select
   
   DateVal = ret
End Function

Public Function Now() As Date
   Now = java#util#Calendar.getInstance().getTime
End Function

Public Function DateSerial(year As Integer, month As Integer, day As Integer) As Date
   'beim Java#util#GregorianCalendar ist der Monat nullbasiert, d.h. Januar = 0
   DateSerial = New GregorianCalendar(year, month - 1, day).getTime
End Function

Private Function getWeekLong(d As Date) As Integer 
   ' Return year of the week
		Dim week As Integer = getWeekShort(d)
   Dim cal As Calendar = java#util#Calendar.getInstance()
		Dim month As Integer 
   Dim year As Integer
   
   cal.setTime d
   month = cal.get(Calendar.MONTH)
		year = cal.get(Calendar.YEAR)

		If (week = 1) And (month = Calendar.DECEMBER) Then
         year = year + 1 
		Else If (week >= 52) And (month = Calendar.JANUARY) Then
         year = year - 1 
		End If

	 getWeekLong = 100 * (year Mod 10) + week
End Function

Private Function getWeekShort(d As Date) As Integer 
   Dim cal As java#util#Calendar = Calendar.getInstance 
   
   cal.setTime d
		getWeekShort = cal.get(Calendar.WEEK_OF_YEAR)
End Function

Public Sub DateDiffTest
   ddt "s", "01.07.2009 10:00:00", "01.07.2009 10:01:00", 60
   ddt "n", "01.07.2009 10:00:00", "01.07.2009 10:01:00", 1
   ddt "h", "01.07.2009 10:00:00", "01.07.2009 11:00:00", 1
   ddt "d", "01.07.2009 10:00:00", "02.07.2009 10:01:00", 1
   ddt "d", "01.07.2009 10:00:00", "12.07.2009 10:01:00", 11
   ddt "y", "01.07.2009 10:00:00", "02.07.2009 10:01:00", 1
   ddt "w", "01.07.2009 10:00:00", "09.07.2009 10:01:00", 1
   ddt "ww", "01.07.2009 10:00:00", "09.07.2009 10:01:00", 1
   ddt "m", "01.07.2009 10:00:00", "01.08.2009 10:01:00", 1
   ddt "q", "01.07.2009 10:00:00", "01.10.2009 10:01:00", 1
   ddt "yyyy", "01.07.2009 10:00:00", "01.07.2010 10:01:00", 1
   ddt "yyyy", "01.07.2009 10:00:00", "01.07.2011 10:01:00", 2
End Sub

Private Sub ddt(Interval As String, ds1 As String, ds2 As String, ret As Long)
   Dim df As DateFormat = New SimpleDateFormat("dd.MM.yyyy HH:mm:ss")
   Dim d1 As Date = df.parse(ds1)
   Dim d2 As Date = df.parse(ds2)   
   Dim d As Long = DateDiff(Interval, d1, d2)
   
   If d <> ret Then
      debug.Print "d1: " & d1
      debug.Print "d2: " & d2
      debug.Print Interval & ": " & ds1 & " - " & ds2 & " = " & d & " <> " & ret
   End If
End Sub