Timestamp show wrong data

android, date, java, timestamp

Solution

`-62135596800000` is 0001-01-03 00:00:00.0 Because by default java uses Julian calendar for dates before October 15, 1582.

The website you are using, uses javascript which uses extrapolated, or proleptic, Gregorian calendar for all dates. From javascript specification

ECMAScript uses an extrapolated Gregorian system to map a day number to a year number and to determine the month and date within that year.

Indeed, in javascript:

new Date(-62135596800000).toUTCString()
//"Mon, 01 Jan 1 00:00:00 GMT"

You can use something like this in java to gain the same results:

GregorianCalendar date = new GregorianCalendar();
date.clear();
//Use Gregorian calendar for all values
date.setGregorianChange(new Date(Long.MIN_VALUE));

date.setTimeZone( TimeZone.getTimeZone("UTC"));
date.setTime(new Date(-62135596800000L));

System.out.println(
        date.get(GregorianCalendar.YEAR) + "-" +
        (date.get(GregorianCalendar.MONTH) + 1) + "-" + 
        date.get(GregorianCalendar.DAY_OF_YEAR) + " " +
        date.get(GregorianCalendar.HOUR_OF_DAY) + ":" +
        date.get(GregorianCalendar.MINUTE) + ":" + 
        date.get(GregorianCalendar.SECOND) + "." +
        date.get(GregorianCalendar.MILLISECOND)
);
//Prints 1-1-1 0:0:0.0

Unfortunately I don't know how to carry out the Gregorian change from `Calendar` to `Date` objects, so I am doing the formatting directly from the calendar object. If I just did `formatter.format(date.getTime())` it would lose the Gregorian change setting and show 3rd day again.

The Julian date is 2 days ahead because according to this, Julian is ahead of proleptic Gregorian by 2 days from 1 BC to 100 AD.

Btw, I recommend using `JodaTime`, it correctly (my opinion, though if you need something more convincing) defaults to pure Gregorian:

DateTime dt = new DateTime(-62135596800000L, DateTimeZone.UTC);
System.out.println(dt.toString());
//0001-01-01T00:00:00.000Z

Problem

Why Timestamp((long)-62135596800000L) return 0001-01-03 00:00:00, but must return 0001-01-01 00:00:00? This service show correct Timestamp here

Original source