JQ Asia will operate the route under QF code share
Yep, they are 3K flight numbers.
Let me just guess what aircraft they'll be using. A subleased Qantas owned A330 or 787.
No, according to the schedule it'll be your standard Jetstar A320.
So what has happened here is that the 'Qantas Group' has simply taken out 1 x A330 worth of J-class seats (and a few economy seats), by replacing the full-service A330 with a Jetstar A320.
Thus dumbing-down the offering as a whole.
It's consistent with the re-config of the A380: reduce J, add a handful of W, and ramp up Y capacity.