Build and Runes
Displacement/dash/jump abilities will let you leap out of his ultimate easily.
Jarvan can be knocked back while casting his Dragon Strike to connect to his flag.
A good Jarvan will lock up your backline and force dashes and flashes to be used. A bad Jarvan will lock up his carries along with him, so make sure to take advantage, especially if the carries are fairly immobile.
Try to not encounter him early. His Dragon Strike ability can shred you.