Add 1 Week to a Date, which way is preferred?

Question

I am reviewing some code at work and came across an inconsistency in how the code handles adding 1 week to the current time and was wondering if there was any reason why one

Answer 1

The two methods might give different results when a change in daylight saving time is involved. Imagine the current time is 23:50 and at 02:00 the clock jumps to 03:00. When you just add 7 days in milliseconds the time would be 00:50 on the following day. Addings 7 days, the resulting time would still be 23:50.

To make the confusion complete, you could also try add(Calendar.WEEK_OF_YEAR, 1), not sure how that would differ though.