Prepare cake mix according to box instructions in 13x9 pan. Let cool. Cut into 1" pieces.
Prepare pudding according to instructions and let sit for 5 minutes to set up.
Warm blueberry jam in a safe bowl for 1 minute in the microwave, mixing half way through.
Layer trifle: 1/4 of Cake, 1/3 of pudding, handful of white chocolate chips, 1/3 of Warmed Blueberry Jam, 1/3 of Cool Whip, Repeat two times. Finish top layer with a generous amount of sprinkles.