Jolteon’s cells generate a low level of electricity. This power is amplified by the static electricity of its fur, enabling the Pokémon to drop thunderbolts. The bristling fur is made of electrically charged needles. It accumulates negative ions in the atmosphere to blast out 10,000-volt lightning bolts. Every hair on its body starts to stand sharply on end if it becomes charged with electricity.
Pokédex entry #135
jolteon is a type electric Pokémon .
jolteon in Pokémon GO
It's possible to hatch jolteon from an egg?
No, jolteon can't be hatched.
Which are jolteon’s strengths and weaknesses?
jolteon is a electric type Pokémon. electric type pokémons are strong against water, flying pokémons but weak against electric, grass, dragon pokémons. They are not affected by ground type pokémons.