There are at least two artists known as JX. JX is a dance music project led by Jake Williams. It started in 1993 regularly featuring guest vocalists. JX are best remembered for their hits "Son Of A Gun", "You Belong To Me" and "There's Nothing I Won't Do".
Jake has also been involved in Planet Perfecto recordings, using a different moniker of Mekka and is now better known as Rex The Dog.
The other is a croatian pop rock gang bang technotronic trip-core superstar, vekii (http://www.last.fm/user/vekii/).

Read more about JX on Last.fm.