J - 7 combinations
309. jack-o-lantern = candle + pumpkin, fire + pumpkin, ghost + pumpkin, ghost + vegetable, light + pumpkin, night + pumpkin, night + vegetable, pumpkin + skeleton, skeleton + vegetable
310. jam = fruit + juice, fruit + machine, juice + machine, juice + sugar
311. jar = bottle + jam, bucket + jam, container + jam, glass + jam
312. jedi = human + lightsaber, knight + lightsaber, lightsaber + warrior
313. jerky = heat + meat, heat + steak, meat + sun, steak + sun
314. juice = earth + fruit, explosion + fruit, explosion + vegetable, fruit + pressure, fruit + rock, fruit + stone, fruit + water, pressure + vegetable, rock + vegetable, stone + vegetable, vegetable + water
315. jupiter = big + planet, big + saturn, cloud + planet, gas + planet, planet + storm