blit = drawing one image onto another.
COnfused now about "clicking on object"?
That doesn't sound like it's to do with drawing a scrolling screen.
Anyway...when scrolling you already have the background drawn once, which is presumably what you drew in the previous iteration.
Use that image, offset by whatever amount you need.
Then draw the missing images.
eg. (and this assumes the currentBackground is the BufferedImage containg the background as last drawn)
If you have mobile content in the background the "blit hero" part will become "blit animations".Code:
blit the bit of the currentBackgroundImage that is still visible onto the newBackgroundImage
Set current = new
Blit background onto screen
Blit the hero onto screen.