I've used ical4j (https://code.google.com/p/ical4j/) for similar problems some months ago.
This should give you a good start to solve your problem.
문제
I'm looking for an open source API
allowing to manage events
in Java
. My needs are to create .ics file
that contains one (or many) event(s) in order to synchronise them.
Also it will be very helpfull if this API can manage update (ie : if we can update event that we first create with the same system).
해결책
I've used ical4j (https://code.google.com/p/ical4j/) for similar problems some months ago.
This should give you a good start to solve your problem.