Yes it is definitely possible, but not a very simple task if you don't get some advice up front.
First and foremost, there is some sample code that is shipped with the Eclipse package at least (CameraDemo) that shows how to create a viewfiender using a Field, Player, and VideoScreen. The biggest issue is third party developers cannot overlay anything on top of the view finder (which is the what they'll call the Field after you set it as such with a VideoControl.
Also, you are very limited to what size you can set the Field -- I only got half size and fullscreen working, some dimensions got ignored and others caused it to not be displayed at all.
Here is some code that shows this:
private Field _videoField; private Player _player; private VideoControl _videoControl;
o snap the picture. To determine what sizeAndEncodingParameters your device supports, you can use System.getProperty("video.snapshot.encodings"); which will return a String that you can iterate over to determine what to use.