The Sony Pictures
While Alex Pettyfer was previously rumored for the role of Jace Wayland, Sony has listed the role on their casting site FaceoftheFan.com:
A male actor is on search that able to play at age 18-25 for the role of Jace Wayland in the upcoming Mortal Instruments movie. Fighting, hunting, and killing demons are the things Jace is good at. Though the jagged scars and black runic Marks on his body are a badge of honor as far as he's concerned, he keeps a lot to himself - until he meets Clary, a mundane girl who can see him, maybe better than he can see himself. The connection that binds them will force Jace to confront the black secrets of a past he never wanted to remember...