So ive always loved Jarvan, and hes a perfect candidate for both tank and dps builds. but i have done my own so enjoy!!! He can jungle, be bot and hes really good at being solo top. And even mid, i tried once and i owned cait

Pros
-He can stay in lane for a long time
-Easy to farm safely even against common solo top champs like nasus
-Every one of his skills are good for his team,
-Good initiator
-Good damage output
-Can destroy ultis wall

Cons
-Low mana pool
-Hard to play, or just need skills to play good
-People can escape your ulti with movement abilities like flash alpha strike

Well its the classic e spell then q spell to knock them up, if you have mana to spare u can also w to slow them so its easier to pursuit. And u can always lock them down with your ulti(or last-hit). You can also use q spell on enemies to give your team armor pen against them.

My runes are typical tank runes with armor seals and magic res glyphs, i have armor pen marks for some extra dmg and my quints are for crit chance which is awesome to crit.

So phage is a really good starting item, because jarvan doesnt have so many chasing attacks except his q,e combo which has long cooldown. But with phage u can run after them easier. and frozen mallet just gives health which is essential to this build. with 2 warmogs frozen mallet and atmas impaler your health can go over 5k health and around 260dmg.