Question:

Would that be difficult to use Java for displaying the image from the webcam connected locally, and capture the image from that?   If yes, would that be a cross platform solution like Java does for other application?

Solution:

It wouldn’t be easy, but if you know a bit of Java you should be able to do it. Do a search on google for “java webcam application” (without the double quotes) and you can find loads of examples.

>  If yes, would that be a cross platform solution like Java does for other application?

It depends if the libraries use native code or not. If you go with JMF (http://java.sun.com/javase/technologies/desktop/media/jmf/) it will be, although you need to use some native code, it comes with all the necessary libraries you need.