Item duplication exploit.

Anything thrown (long press screen) or dropped (long press hotbar) through a nether portal and collected on the other side will reappear on the ground as an item each time you reload the game in single player. This gives an endless supply of collecting whatever items you've tossed through a portal each time you reload the world. This can accumulate too, so I throw something through, duplicate a few times, drop something else through, and now both are duplicating...