She can use any letter (or symbol) that she wants to. Since w is the first letter of width, it seems like a good choice.
She says "The j represents anything you want it to", it says so on her official website. Her real name is Jessie Cornish, so Jessie J was just a great stage name.
Jessie Camacho goes by Jessie.
Jessie Starnes goes by Jessie.
Jessie Bond goes by Jessie Bond.
Jessie Monteiro goes by Jessie Bear.
Jessie J is a Christian.
Get it from Jessie
Debby Ryan
Jessie Hail's birth name is Jessie Hail.
Jessie is bi
The Jessie Belle was a stemboat.
there is "jessie's girl"