The i18n Cookbook - recipies for a global society

Problem:

You want to format a span of time.

Solution:

As of version 4, icu4j contains a DateIntervalFormat class.  This class makes it relatively easy to format an interval value.  The format will automatically format as compactly as possible. For example: if the difference between the two dates is only a few hours and both dates occur on the same day, the year, month, and day parts of the date will be omitted.

Calendars and date formatting are central to a properly internationalized application.  Java provides several classes that are very useful to the localization developer for handling dates and times. 
 
Java's Calendar class and its sub-classes handle the complex date calculations that go with Chinese, Islamic, Hebrew, and Gregorian calendars, as well as a number of others.
 
Java's DateFormat class handles formatting dates and times in a locale appropriate manner.