Unable subtract days from date in java

Question

I want to subtract days from date in java. But I dont want to use external libraries. I have referred some of questions from stackoverflow but they are suggesting to use external libraries. So I have applied following logic

noOfDays = 24;
Date compareDate = new Date(currentDate - noOfDays * 24 * 60 * 60 * 1000);
System.out.println("compare date " + compareDate);

It is working fine till 24 days.But after 24 days it is giving unexpected result. Is there any solution to this ?

My current time is in epoch. How can I fit that in calender object. — sdk, Apr 12 '16 at 14:14
A day is not always exactly 24 hours (think about daylight savings transitions, where a day can be 23 or 25 hours), so subtracting number of days times 24 hours is not always correct. — Jesper, Apr 12 '16 at 14:16
Use the new Date-Time API in Java 8: https://docs.oracle.com/javase/tutorial/datetime/ — jhyot, Apr 12 '16 at 14:22
@SuyashKharade Please search Stack Overflow before posting. This has been addressed many many times already. — Basil Bourque, Apr 12 '16 at 19:10
I have checked all the questions. Everyone is suggesting third party libs. That's why I posted this one. — sdk, Apr 13 '16 at 03:19

score 4 · Accepted Answer · answered Apr 12 '16 at 14:13

4

Use java.util.Calendar. Something like that:

Calendar c = new Calendar()
c.setTime(currentDate);
c.add(Calendar.DAY_OF_MONTH, noOfDays)
compareDate = c.getTime()

answered Apr 12 '16 at 14:13

Jens

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Thanks @Jens. It solved my problem. – sdk Apr 12 '16 at 14:24
This Answer is now outdated. See the modern solution using *java.time* in the [Answer by assylias](https://stackoverflow.com/a/36576345/642706). – Basil Bourque Jun 20 '19 at 20:42

score 1 · Answer 2 · answered Apr 12 '16 at 14:30

1

You can use a LocalDate (which is part of the JDK since Java 8):

LocalDate today = LocalDate.now();
LocalDate compareDate = today.minusDays(24);

answered Apr 12 '16 at 14:30

assylias

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Arnaud · Answer 3 · 2016-04-12T14:20:32.177

You computation is about integers, which won't fit higher values than the max integer value.

Declare your variable as a long :

long noOfDays = 24;
Date compareDate = new Date(currentDate - noOfDays * 24 * 60 * 60 * 1000);
System.out.println("compare date " + compareDate);

However, as the comments said, this is not the best approach for substracting days, so have a look at better solutions in other answers.

Unable subtract days from date in java

3 Answers3