title: Java: how to calculate number of days from the beginning of time (with time zones)
body: <p>I want to calculate the number of days from the "beginning of time" to a current date. This could be easily achieved with a simple calculation (timestamp / 24 / 60 / 60 / 1000 = daysFromBeginningOfTime) but the twist is that i need to be aware of time zones as well. The timestamp is the same everywhere in the world but when you parse it with the proper time zone then it reflects the differences between locations so using just the timestamp doesn't work and i don't want to handle all the time zone transitions myself.</p>
  
  <p><strong>Example</strong>:
  if it's 23:30 in London and the day number is 18843 then in Amsterdam it's 0:30 and the day number should be 18844.</p>
  
  <p>I looked at <code>joda.time</code> but didn't really find what i was looking for.
  Anyone have any ideas?</p>