Java APIs

Hi,
i want to create a very easy multiplayer shooter. At first view, it seems to be easy to program but:
Positions of the players are transfered frequently by UDP. It is not fatal if one UDP package is missing ( the next one will come within milliseconds).
But what if a player shoots? If the UDP package which transfers the shoot is missing, it would be fatal.
Is it posible to use TCP for shots? Or is UDP still OK? Or do i have to use that shitty, hard reliable UDP?
By the way, what's the difference of TCP and reliable UDP. why is TCP still used although there is a faster RUDP?
thx,

chr