title: Easiest way to calculate offset between two timezones Scala/Java
body: <p>I din't find good answer how to easy calculate timezone offset for given point of time in Scala/Java.</p>
  
  <p>Given:</p>
  
  <ul>
  <li>date with time</li>
  <li>timezone 1</li>
  <li>timezone 2</li>
  </ul>
  
  <p>Requirements:
  calculate offset for particular date in timezone 1, required to move this date to timezone 2.</p>
  
  <p>Example:</p>
  
  <p>datetime = 2017-10-23 00:00:00 in <code>America/Los_Angeles</code> timezone 1,</p>
  
  <p>timezone 2 = <code>Europe/Paris</code></p>
  
  <p>Offset should equal +9, it can be used to move date from timezone 1 to timezone 2.</p>