I have seen several other platformer games and was thinking of creating a different platform game experiment myself. I do have other things to make before I make such a platformer.
If you place the collided area in a array you might be able to quickly see if a player is on the ground.
This weekend I did not read a lot in the Java book. I had no Internet access either.
I was thinking of making a filthy platformer. Where you shoot the enemies with diarea. (player thinks he's a skunk) I might call it - Diarea man