This build focuses on maximizing J4's utility (Max CDR) and his tankiness (shield scaling with HP). To win with this build you teamfight, maximizing your shield value so you can stay alive, while using your CC (Flagdrags + Slows) and your ult to disrupt the enemy frontline as well as their backline. Besides being able to engage whenever you want (typical for J4), and keeping the whole enemy team under crowd control or zoned, while having the shields to do so, you also shred their armor (Q, Black Cleaver) and increase your own ADC's DPS (E, Zeke's Convergence) and survivability (Font of life).

With this low-damage and low burst build you tend to primarily look for W shield and slow into an auto to both proc your passive and grasp every now and then. When your opponent gets low you can threaten him by going for the E into Q.
Every now and then you can use your Q and E to lasthit, even from range.
Don't forget this build focuses on getting to a 3 item midgame powerspike, which means that you don't have to look for a lead in the laning phase.

You can tell the obvious hinder in building like this. You deal no damage. You're not entering a sidelane to fight a champion, you're merely there to waveclear with sunfire cape. You can't catch people off-guard (unless they're low) on your own. You will barely get any kills. You will finish the game with less damage dealt to champions than your support. Yes, all of this is true, but the trade-off is immensely overlooked and underrated.
First of all, you max W first and E second (no point in maxing Q unless your team is almost full AD and you need the shred on Q). Your W will make you tanky early on, surviving trades and all-ins you wouldn't be able to by maxing Q. Your E also gives you, as well as your whole team, more attack speed in skirmishes and early teamfights.
Your roam/TP play potential also increases. Your tank stats make it possible for you to tank enemy turrets longer after diving onto enemies. Laneswaps also benefit you more since you just have to waveclear with sunfire cape under turret, while being tankier than usual, making it hard for you to get dove. When matching a split push champion in a sidelane during the mid-game, you wouldn't be able to fight them anyways since those champions are designed to fight way more than Jarvan is. Your tankiness makes it harder for them to dive you when you waveclear as they splitpush.

This is by no means the end product of my Jarvan IV build.
This is just a little start.