Klase u BF3
Assault/Medic
The Assault and Medic a classes have been combined now, where the Assault class can either chose to heal/revive teammates, or you can opt for a grenade launcher instead of the revive kit, if you want more firepower.
Support
The Support class is now the one handing out ammunition, and can also provide covering fire. You can mount your LMG and if fire in the direction of the enemy, you’ll get special bonus points for providing covering fire for your teammates. You can also select an assault rifle with a flashlight for the dark parts of maps (like tunnels), instead of the LMG.
Engineer
The Engineer retains much of his role and load-out from Bad Company 2, you’re equipped with rocket launchers against enemy armor, and a repair tool to fix friendly vehicles, and a sub machine gun.
Sniper
The Sniper has the same role as in previous Battlefield games, and is armed with a sniper rifle, C4 explosives, and spotting gear.