Sludge, certainly a catapult is one way of doing it, but the Harrier, both RN and USN, uses (used) the "ski-jump". In the Falklands nastiness it was the only way the Harriers were launched, and they were fully loaded.
In fact there is a video of the F-35 using a ski jump on the USS Wasp. The difference is the F-35, because of its STOVL capability has a lot more engineering (i.e weight) than the F-18 or it's Chinese equivalent.
It is interesting that the Chinese use coloured shirts (imitation is the sincerest form of flattery). Granted the film clip is a great propaganda boost but I think the Chinese are a lot closer to being a fully operational force than many would like to admit.
Cheers,
Tregarth