Wellcome to my Jarvan build!.I prefer playing Jarvan as an semi DPS/TANK char.This combines greatly the ability to help the carries do damage as well as keeping yourself alive in team fights with good amounts of hp-recistances and be feared of your hight amounts of bust damage!.Enjoy :)

Pros:
-Powerfull passive great for farming and harassing.
-Builds up good AS on his own because of Dermacian Standard skill.
-Great distance closer by using his abilities in the right way.
-Can change the flow of the fight by using his ultymate in the right place and time.
-Can jump right on the enemy team's squishes and paint with their blood the grass!
-Many ways to play and build him.Can also serve as a main tank if needed(but not with this build).
-Not very item dependable
Cons:
-Really mana hungry and you should be carefull to have at least 100 mana to combo your offensive abilities.
-Not carefull aiming results in failure of your abilities.
-Need to remember to break the baricade of your ultymate if needed.
-Late game phases are not the favorite for this character
-Rather low movement speed

ARP Marks and Quitessensces secure a very good amount of damage late and early game
Critical Seals:This build is critical dependable;.Those runes work perfectly with your overall build
CDR Glyphs:Those make your life much easier as your spells are important for killing,offtanking and in general being a real threat over your opponents.If you have hard time manipulating your mana you can swap them for MP5 runes.

Masteries:
For masteries I use my favorite 22-08-0 build.Why?.I pick up the best spells for DPS chars as well as gaining dome mana regen faster lvlup and improved ghost to help my laning phase.This provides a very good nuke with average mana regeneration.You can also go for a more tanky approach by going 9-21-0.Feel free to use something diffrent if it suits you better.

Items:
I begin with a Dorans blade for good survive ability and damage.Be carefull though because you wont be carrying a potion.The small amount of lifesteal will be more than enouph to keep you in lane untill lvl 6.
Y Ghostblade:One of my favorite items in the game.And the active will make you kill very fast any enemy combined with frequently criticals and good amounts of damage.
Frozen Mallet:With this item you will be glued onto your targets combined with Ghostblade's passive.Also the hight amount of health will give you the chanse to play more aggresively and help your team to achieve more kills.
Atmas Impaler:Some usefull resistances as well as nice critical strike chance and damage with your Frozen mallet.
Executioner's Calling:Even more crit chance for you to become more deadly.It has a very nice lifesteal passive and gives you the ability to kill chars like Mundo and Swain.
Infinity Edge:Expensive but really worth taking.I pick it last because your damage is more than enough to slay early and mid game.With this item you deal massive burst damage with your critical hits as well as a nice base damage.The last buff of IE made this item even stronger and defenetly worth getting

Summoner Spells:
I prefer using Exaust+Ghost in Jarvan.By far the best skills for chasing and also providing escaping uses.But as far as i've seen summoner spells are not a must.People play better with the summoner spells they are used to play with.So you can pick either flash ignite etc.Just dont pick support spells exept clarity witch is usefull in Jarvan

Early game you can play aggresively and harass.Your ranged spells deal very good early game damage.Just be carefull of your mana pool.Push for fist blood!.Jarvan is very capable early game.Dominate the lane!.A good Jarvan is an aggresive Jarvan!!!.Later focus on the squishies targets and protect your carries.You will ofter be working as an offtank.Use your ulty wisely and try to get inside the people your team has to focus.Pretty much thats it in playstyle!.If you play Jarvan once you will feel like you had played him a hundred times :)

Thanks for reading my Jarvan build as well as the tips i've written above :).Comment and rate.Also the item order is not carved in stone;Gl & HF.I aprettiate critisim.Trial and error makes perfection :)...(almost!)