Java Date start epoch

Question

The java.util.Date class is based on the number of seconds since 1 January 1970 00:00 GMT. So why does this code

System.out.println(new Date(0));

print Thu Jan 01 01:00:00 GMT 1970? My local time zone is GMT, so I expected it to print 00:00:00 GMT.

I have reproduced `Thu Jan 01 01:00:00 GMT 1970` on my Java 9 after setting my JVM’s time zone to Europe/London. — Ole V.V., Feb 25 '18 at 12:20

score 5 · Accepted Answer · edited Feb 25 '18 at 12:48

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There is an interesting reason for this. Refer (BST Offset bug report) . It says, "and the experiment with British Standard Time from 1968 to 1972, by which the time was advanced by one hour from GMT throughout the year." And further: “The local time produced by Date.toString() is historically correct, except for the time zone abbreviation. It should be "BST" (British Standard Time for this case), but it's a known limitation of the current TimeZone implementation.”

edited Feb 25 '18 at 12:48

Ole V.V.

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answered Feb 23 '18 at 10:41

CGS

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Phantastic EU reminiscent fact. – Joop Eggen Feb 23 '18 at 10:45
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Interesting tidbit of history, but it does not explain why the 1 AM in *GMT* is displayed. Your answer would explain a display of *BST*, but that is not what the Question reports. – Basil Bourque Feb 24 '18 at 05:17
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@BasilBourque, correct, I edited the answer. Interestingly the bug is in the modern API too. `Instant.EPOCH.atZone(ZoneId.of("Europe/London")).format(DateTimeFormatter.ofPattern("EEE MMM dd HH:mm:ss zzz yyyy", Locale.ROOT))` too produces `Thu Jan 01 01:00:00 GMT 1970` on my Java 9. – Ole V.V. Feb 25 '18 at 12:52

score 1 · Answer 2 · answered Feb 23 '18 at 10:36

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This link might help. I'm quite a novice at the Date class, but I figured this could help somehow.

answered Feb 23 '18 at 10:36

Robo Mop

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PS: I wanted to comment this, but can anyone tell me how to add links in comments? I'm really dumb :P – Robo Mop Feb 23 '18 at 10:37
Yes. Click the 'help' link that's next to the comment textbox. The page will expand and show you how to do things, including adding links, while you are still typing in the comment box. – DodgyCodeException Feb 23 '18 at 10:57
@DodgyCodeException Thanks! – Robo Mop Feb 24 '18 at 05:05

score -1 · Answer 3 · answered Feb 23 '18 at 10:25

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Unix Epoch Time is a system of time describing how much time has elapsed since January 1st, 1970.

Therefore, when you create a new java.util.Date object with 0 milliseconds elapsed, it will return January 1st, 1970.

What you are looking for is here.

answered Feb 23 '18 at 10:25

Austin Schaefer

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I don't understand. If zero milliseconds have elapsed, then why will it display 1 A.M? – Robo Mop Feb 23 '18 at 10:42

Java Date start epoch

3 Answers3