I don't like how this discussion has devolved into bickering over whether or not the J-15 is a successful project. It's been two pages and no one has brought up any concrete points, and in an unsuitable thread for it, no less.
The J-15 is objectively not a good aircraft, especially if operating from a STOBAR carrier. It was a successful project only to the extent that it gave Liaoning and Shandong something resembling an air wing. Other than that, it is plagued with problems - maximum takeoff weight, reliability, size, and so forth.
The J-15 can take off with full load only from the rearmost position. Anywhere else, and you might as well have a flock of ducks for an air wing. This is probably the most severe limitation, but it can be remedied with a catapult-launched version, taking off from CATOBAR carriers. Aside from that, with only ~20 aircraft operated in the last 6 years, there has been two crashes, highlighting unspecified issues with reliability. We don't know exactly what's wrong but it's safe to guess that there are problems.
It is also a very large aircraft, which takes up a lot of deck/hangar space. If the Chinese Navy operated F/A-18s instead of J-15s, they could probably squeeze 35-40 planes onto each carrier instead of only 24-30. Of course, there is a trade-off in terms of how much fuel/ordnance each aircraft can carry and how far it can fly, so whether or not the PLAN will use a smaller airframe for its next-generation carrier-based fighter is something we'll find out soon.
At this point, the J-15 era is over. It's a successful demonstrator but its value stops there. It's finished, and the fact that no more airframes are being produced says a lot. The question now is if they will rush development of the next-generation aircraft that do not have these issues and limitations, or if they will take it slow, and restart J-15 production in the interim. The popular concensus is the former, but it is difficult to say with any kind of confidence.