The reason that you're not seeing the oval is that you're drawing the image onto its own Graphics
object. Replace:
dbg.drawImage(dbImage, 0, 0, this);
with
g.drawImage(dbImage, 0, 0, this);
Also better not to override paint
in a top-level container but rather override paintComponent
in a sub-classed JComponent
. Also remember to call
super.paintComponent(g);