How to draw a filled circle and how to track its position

first time asking question on stack overflow, but I plan on creating a graphics window, having randomly placed circles and tracking that position of each circle so that I can call the information later. I realize I need to create an array but what resources will i need to create the graphics window, create the randomly sized circle and store the area that it covers?

I seem to find how to make circles but they are either not filled or the information I get is using about 5 different resources which am unable to recreate in eclipse myself for various reasons