I'm creating an image annotation tool.

Description: The user is able to load up an image and
create/edit/load/save markings on it, such as circle, points, polygon,
etc. Each marking will be digitized and stored in a database.

What is the best approach to do that?

I'm not too familiar with overlapping JPanel.. (Possible?) One way to
do it is to add a new layer whenever a marking is created.

Also, I'd like to allow user to UNDO their selections, so how do I go
about clearing the markings?