Best way to access web camera in Java

I think the project you are looking for is: https://github.com/sarxos/webcam-capture (I'm the author)

There is an example working exactly as you've described - after it's run, the window appear where, after you press "Start" button, you can see live image from webcam device and save it to file after you click on "Snapshot" (source code available, please note that FPS counter in the corner can be disabled):

The project is portable (WinXP, Win7, Win8, Linux, Mac, Raspberry Pi) and does not require any additional software to be installed on the PC.

API is really nice and easy to learn. Example how to capture single image and save it to PNG file:

Webcam webcam = Webcam.getDefault();
webcam.open();
ImageIO.write(webcam.getImage(), "PNG", new File("test.png"));