At least the outer 33 moons orbit in the opposite direction in which Jupiter spins, which is unusual and indicates the moons were asteroids that were sucked into Jupiter's orbit after the initial system was formed. read more
Regarding the rest of them, many astronomers think that the formation of Jupiter and it's satellites may have mimicked on a small scale the formation of the Sun and the inner planets, with generally denser moons forming closer to the intense heat of the young Jupiter. read more