See. Jayce has a lot to offer in the jungle since his abilities and the items that are built for him complete eachother, and his combo does a lot of damage early AND late game.

A few things that makes jayce a viable jungle are:
1. His AoE damage that helps him slaying smaller monsters in the jungle;
2. His Engaging/Disengaging abilities such as his Q or E while in hammer mode.
3. His Build/Kit that gives him enough mana/ad/tankyness to 1vs1 anybody, even if you can't beat 'em, you can run away from them with your E.
4. He can both Start a teamfight or assassinate isolated targets because of his combo and his sustain (items), that will make his abilities so annoying that the other carries won't even try anymore.

It's a pleasure, i'm GinWinsky from the BR servers of LoL and i'd like to introduce you and everyone to new junglers. \o Hope you enjoy it and try it out.

Hugs and Kisses,
xoxoxo \o