Lol are u serious? Jax is powerful if u build him rite or u know that combo lol
I normally jungle with jax so this is my jungle build, it maybe the recommended but I tried all other builds and this is the best for me.
cloth armour and 5 pots, get lvl1 boots then wriggles. Get sheen and build into tri force, rageblade and a gunblade. After these items u should start build sine sort of defense items so I usually pick up guardian's angel or randuin's.
If u get ur gunblade u can basically in my experience kill an adc in around 3 seconds (without armour)