The Java class for converting a moment in time (java.util.Date) to fields that represent the date (day, hour, minute, etc.).
Through Java 7, the official class for representing a moment in time, using a thin wrapper around the number of milliseconds from epoch (1970-01-01)
"Construct java.util.calendar is comparative slower than java.util.date"
from question "Migrating from Java Calendar to Joda Date Time"