Question

I am looking for the best way to add milliseconds to a Java Date when milliseconds is stored as a ‘long’. Java calendar has an add function, but it only takes an ‘int’ as the amount.

This is one solution I am proposing…

Calendar now = Calendar.getInstance();
Calendar timeout = Calendar.getInstance();

timeout.setTime(token.getCreatedOn());
timeout.setTimeInMillis(timeout.getTimeInMillis() + token.getExpiresIn());

Any other suggestions?

Answer 1

Your solution looks nearly fine to me, actually. I originally posted an answer going via Date, when I hadn’t taken getTimeInMillis and setTimeInMillis into account properly.

However, you’re calling setTime and then setTimeInMillis which seems somewhat redundant to me. Your code looks equivalent to this:

Calendar timeout = Calendar.getInstance();
timeout.setTimeInMillis(token.getCreatedOn().getTime() + token.getExpiresIn());

A generally nicer alternative would be to use Joda Time though 🙂 It’s generally a much nicer date/time API.