On almost all CX flights, the meal service is soon after take off, and the second meal is 2 hours before landing. Then there are snacks on demand (noodles, sandwiches). Rarely do any flights deviate from this as the idea is to allow the passenger to sleep for as long as possible in the middle.
I can't remember on 840, but definitely not on 830 (9:30am departure)...in J (and presumably Y as well) they actually do the second meal about 7 hrs before landing, or right around half-way through. Real pain in the a$$ if you're trying to sleep. Since 830 departs in the morning, I always try to stay awake 5-6 hours before making myself sleep so I can get better adjusted to NY time. But because of that, inevitably 2 hours or so after I fall asleep the lights get flipped back on the meal carts are coming back through the aisles. I never understood why they did that (especially since two hours before landing would be right around lunch NY time anyway). I've just taken to asking FAs to save me a meal and I have them serve it an hour or two before landing.