Jarvan is at heart an AD off/tank Character with a lot of potential to carry a team. This build has both Health to keep your self alive long enough and enough damage to solo a carry (most of the time). Hopefully this guide and build help you dominate the Summoner's Field and make Jarvan IV your favorite as he is mine.

When playing against all AD characters you should start the game with Berserker's Greaves instead of Mercury Treads.
If they have a **** load of AP on the other team you should get your Force of Nature after you have gotten your Trinity force unless your team has already feed their AP too much, this replaces your Infinity Edge.
If additional health is required to tank even harder then is necessary then u should also get this after Trinity Force replacing the Infinity Edge opening.
If your more of a tanky support then you can get Starks Fervor for your carry as well as yourself and a Rodem's omen. as well as a Shield of Aegis. (you wont be able to actually do basic attack damage this way though).

I'm sure if you've bought Jarvan its because you really like his skill combo.
Start with you Demacian Standard on top or behind a enemy champ straight into your dragon strike aiming directly at the Standard.
This combo will put u either on top of the enemy champ or behind him knocking him up in the process.
Directly after the enemy is knocked up you should use your Ultimate (Cataclysm) doing a **** load of Damage due to the lowered Armor that Dragon strike gives.
once he decides he has to fight or tries to run use your Golden Aegis to slow the enemy champ and give yourself a Armor shield.

When I use Jarvan i have no need for Flash or Ghost due to his Demacian Standard and Dragon Strike. this Combo can get you over bascially any wall.
I recommend Ignite and Exhaute to help gank enemy characters as well as help yourself one v one enemy champs when you need that clutch ACE or when your caught alone with a Champ.