How to subtract X day from a Date object in Java?

Question

Java 8 and later

With Java 8's date time API change, Use LocalDate

LocalDate date = LocalDate.now().minusDays(300);

Similarly you can have

LocalDate date = someLocalDateInstance.minusDays(300);

Refer to https://stackoverflow.com/a/23885950/260990 for translation between java.util.Date <--> java.time.LocalDateTime

Date in = new Date();
LocalDateTime ldt = LocalDateTime.ofInstant(in.toInstant(), ZoneId.systemDefault());
Date out = Date.from(ldt.atZone(ZoneId.systemDefault()).toInstant());

Java 7 and earlier

Use Calendar's add() method

Calendar cal = Calendar.getInstance();
cal.setTime(dateInstance);
cal.add(Calendar.DATE, -30);
Date dateBefore30Days = cal.getTime();

@JigarJoshi it's the good answer, and of course also @Tim recommendation to use .joda-time.

I only want to add more possibilities to subtract days from a java.util.Date.

Apache-commons

One possibility is to use apache-commons-lang. You can do it using DateUtils as follows:

Date dateBefore30Days = DateUtils.addDays(new Date(),-30);

Of course add the commons-lang dependency to do only date subtract it's probably not a good options, however if you're already using commons-lang it's a good choice. There is also convenient methods to addYears,addMonths,addWeeks and so on, take a look at the api here.

Java 8

Another possibility is to take advantage of new LocalDate from Java 8 using minusDays(long days) method:

LocalDate dateBefore30Days = LocalDate.now(ZoneId.of("Europe/Paris")).minusDays(30);

Simply use this to get date before 300 days, replace 300 with your days:

Date date = new Date(); // Or where ever you get it from
Date daysAgo = new DateTime(date).minusDays(300).toDate();

Here,

DateTime is org.joda.time.DateTime;

Date is java.util.Date

Java 8 Time API:

Instant now = Instant.now(); //current date
Instant before = now.minus(Duration.ofDays(300));
Date dateBefore = Date.from(before);

As you can see HERE there is a lot of manipulation you can do. Here an example showing what you could do!

DateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
Calendar cal = Calendar.getInstance();

//Add one day to current date.
cal.add(Calendar.DATE, 1);
System.out.println(dateFormat.format(cal.getTime()));

//Substract one day to current date.
cal = Calendar.getInstance();
cal.add(Calendar.DATE, -1);
System.out.println(dateFormat.format(cal.getTime()));

/* Can be Calendar.DATE or
*  Calendar.MONTH, Calendar.YEAR, Calendar.HOUR, Calendar.SECOND
*/

With Java 8 it's really simple now:

 LocalDate date = LocalDate.now().minusDays(300);

A great guide to the new api can be found here.