missing days : Java Glossary

2007-10-05 by Roedy Green ©1996-2008 Canadian Mind Products
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missing days

The original Julian calendar had a leap year every four years. The inaccuracy this simple scheme generated was apparent way back in the 1500s. At the suggestion of astronomers Luigi Lilio and Chistopher Clavius, Pope Gregory XIII introduced the new Gregorian calendar, in which every 100 years is not a leap year and every 400 years is. He decreed the flip-over date would be 1582-10-05. To get the calendar started and in sync with the sun, he declared that there would be 10 missing days in 1582-10. 1582-10-05 to 1582-10-14 never happened.

Only Italy, Poland, Portugal and Spain went along with the new calendar immediately. One by one other countries adopted it in different years.

The rest of the world was reluctant to change the calendar, and only gradually implemented it, some in the 20th century. There are even groups today, such as Greek Orthodox church, Russians and Muslims who don’t use the Gregorian calendar.

Britain and its territories (including its colonies that later became USA and Canada) adopted the Gregorian correction in 1752-09. By then, 11 days had to be dropped. 1752-09-03 to 1752-09-13 never happened.

The Gregorian calendar corrects the length of the year to year to 365.2425 days. It gets ahead 1 day every 3289 years.

BigDate will use either Pope Gregory’s correction or the British one, depending on which you configure.

You can configure the flip-over date from Julian to Gregorian with GregorianCalendar. setGregorianChange. By default the date is Pope Gregory’s 1582-10-05

Learning More

Sun’s Javadoc on the GregorianCalendar class : available:

on the web at java.Sun.com
in the JDK 1.6.0_06 or in the older JDK 1.5.0_15 or the even older JDK 1.4.2_17 on your local J: drive.

BigDate
Calendar FAQ
GregorianCalendar
Julian date
leap second
leap year

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