title: Difference between Calendar.getInstance() and GregorianCalendar.getInstance()
body: <p>Ever since it was first introduced to replace <strong>Date</strong> I have been using the static method <strong>Calendar.getInstance()</strong> to get a new <strong>Calendar</strong> object. I have never had a problem but I just wondered for some reason if it were better to use the <strong>GregorianCalendar.getInstance()</strong> method instead.  </p>
  
  <p>Is it possible my programs will run in some locale or some JVM somewhere where the superclass version will return an object class I wasn't expecting?  Has there ever been an implementation of <strong>Calendar</strong> <em>other than</em> <strong>GregorianCalendar</strong> that ever made it into wide use?</p>
  
  <p>As I said I'm not having a problem at the moment but I am always looking to improve my practices.  </p>