Limitation on year amount in org.apache.commons.lang.time.DateUtils

Question

Why does org.apache.commons.lang.time.DateUtils have in its source code a limitation on the number of years?

if (val.get(Calendar.YEAR) > 280000000) {
    throw new ArithmeticException("Calendar value too large for accurate calculations");
}

I wanted to know, why exactly 280 millions, not for exmaple 285. I guessed already, that we won't have java anymore. Also I know, that Long can hold 292278994 years in milliseconds.

The year 280 million AD? Well, I'd bet we won't have Java anymore by then. — Thomas, Mar 23 '17 at 14:02
@Thomas: no enough to calculate the end of the universe. And maybe you want to do that now, not when it's too late. — Thomas Weller, Mar 23 '17 at 14:03

score 3 · Answer 1 · edited May 23 '17 at 11:54

3

Well, I'd have to guess but this is probably related to: When will the java date collapse?

Since year 280,000,000 is very close to the maximum of 292,278,994 there might be any anticipated accuracy problems, hence the message says

Calendar value too large for accurate calculations.

Btw, we now know when the universe is going to end: Sun Aug 17 07:12:55 GMT 292278994 - ;)

edited May 23 '17 at 11:54

Community

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answered Mar 23 '17 at 14:09

Thomas

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kmkaplan · Accepted Answer · 2017-03-23T14:17:44.053

2

As indicated by Thomas there are woes due to date being stored in 64 bits. This guard was introduced in 2004. See the test case for details and also bug LANG-24.

edited Mar 23 '17 at 14:17

answered Mar 23 '17 at 14:12

kmkaplan

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Nice find. They already knew it by then: `Date endOfTime = new Date(Long.MAX_VALUE);` – Thomas Mar 23 '17 at 14:14
Thank you. You showed me direction to explore. – OneMore Mar 24 '17 at 15:26

Limitation on year amount in org.apache.commons.lang.time.DateUtils

2 Answers2