[java] Adding days to a date in Java

How do I add x days to a date in Java?

For example, my date is (dd/mm/yyyy) = 01/01/2012

Adding 5 days, the output should be 06/01/2012.

Here is some simple code to give output as currentdate + D days = some 'x' date (future date):

DateFormat dateFormat = new SimpleDateFormat("dd/MM/yyyy");

Calendar c = Calendar.getInstance();    
c.add(Calendar.DATE, 5);
System.out.println(dateFormat.format(c.getTime()));

java.time

With the Java 8 Date and Time API you can use the LocalDate class.

LocalDate.now().plusDays(nrOfDays)

See the Oracle Tutorial.

Calendar cal = Calendar.getInstance();    
cal.set(Calendar.DAY_OF_MONTH, 1);
cal.set(Calendar.MONTH, 1);
cal.set(Calendar.YEAR, 2012);
cal.add(Calendar.DAY_OF_MONTH, 5);

You can also substract days like Calendar.add(Calendar.DAY_OF_MONTH, -5);

If you're using Joda-Time (and there are lots of good reasons to - a simple, intuitive API and thread-safety) then you can do this trivially:

(new LocalDate()).plusDays(5);

to give 5 days from today, for example.

EDIT: My current advice would be to now use the Java 8 date/time api

SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy");
Calendar c = Calendar.getInstance();
c.setTime(new Date()); // Now use today date.
c.add(Calendar.DATE, 5); // Adding 5 days
String output = sdf.format(c.getTime());
System.out.println(output);

Simple, without any other API:

To add 8 days:

Date today=new Date();
long ltime=today.getTime()+8*24*60*60*1000;
Date today8=new Date(ltime);