Jarvan is a jungler with very strong ganks and lots of cc. My build is not a standard Jarvan build, but it's strong, too. It has an a bit weaker erly game, but scales better in the lategame. The biggest con of this build is that you need to stack your devourer item up, so you dont deal very much damage if you fall behind.

Pros

-tons of damage
-tons of cc
-you can be very tanky
-good sustain in the jungle
-scales better into lategame than other Jarvan builds
-strong in teamfights
-works great together with aoe spells

Cons

-knock-up can be dodged
-weaker in th earlygame than other Jarvan builds
-has mana problems in the jungle