Bulletproof (1996)

A none-too-bright criminal, Archie Moses (Adam Sandler) works for drug kingpin Frank Colton (James Caan) and remains oblivious to the fact that one of his closest buddies is actually an undercover police officer named Jack Carter (Damon Wayans). After Moses accidentally shoots Carter, the cop must recover and then bring the two-bit thug in to take the stand against Colton. With Carter and Moses on far from good terms, however, the trip does not go well.