If I have a bunch of video files, all in precisely the same format, shape, whatever, then can I play them back seamlessly without jumps or gaps? The effect from the end user's point of view would be as though they are watching one video.
I understand that this is possible in DirectX, but I'd rather use Java if possible.
If you want to play media in Java, the Sun standard is JMF (http://java.sun.com/javase/technologies/desktop/media/jmf/) which unfortunately has been dormant for quite a while.
The FMJ project (http://fmj-sf.net/) is API-compatible and under active development.
I cannot answer your question better, but hopefully this can get you further.