This pull request replaces calls to deprecated methods from `java.util.Date` with near-equivalents in `java.util.Calendar`.

Author: Tor Myklebust <tmyklebu@gmail.com>

Closes #4668 from tmyklebu/master and squashes the following commits:

66215b1 [Tor Myklebust] Use GregorianCalendar instead of Timestamp get methods.