The word is that there are now 12 J-15.
As tphuang points out, the latest pre-production J-15 seen was 0008 (556). I suppose that this aircraft and the others seen with CFTE numbers have been assigned to the carrier air regiment: there has been a number of pictures of them at Xingcheng-2 (Huangdicun) carrier air base.
The Lot 01 J-15 0104 was seen in one of the pictures from Shenyang AC, so it is unlikely to be in service now. This lot is expected to comprise 24 planes.
I do not know how far production of J-15S has proceeded, but they would certainly seem to need two-seaters for carrier training.
I would think that it has been posted already, but anyway: It was announced on 10 May that the Navy's first carrier-based air formation was officially formed today in the Bohai Bay, marking the construction of aircraft carrier combat effectiveness of troops entered a new stage. The carrier-based aviation unit is the core of the construction of aircraft carrier combat effectiveness, by carrier-based aircraft flying units, maintenance support troops; equipped with
carrier-based fighters = J-15
trainer aircraft = JL-9H
and anti-submarine, rescue, warning and other ship-borne helicopters = KA-28PL, KA-28PS and KA-31
I think this must resurrection of 7 Naval Aviation Division, which in 1988 became the Naval Aviation Training Base at Shanhaiguan, where 2 Training Regiment (ex 7 Div 19 Regt) is now flying some 20 JL-9H.
The KA-28/KA-31 helicopters are at present based at Ningbo-Zhuangqiao in East Sea Fleet.