IntelliJ IDEA: Move line?
Open Setings -> Keymap then search for "move line" via the upper right searchbox.
Under the Code folder you'll see:
- Move Statement Down
- Move Statement Up
- Move Line Down
- Move Line Up
The actions you're looking for are (as you may guess) the move line actions.
As other people have said this is already available as a command. You can configure the short cut to your liking, but by default (at least in IntelliJ 10) it is bound to ALT + SHIFT + ↑ and ALT + SHIFT + ↓