Preheat oven to 350 degrees.
Spray Pam on the inside of a 9 x 13 x 2 cake pan.
Prepare box cake mix batter according to package directions. Pour the batter into the cake pan. Drain and chop the cherries into small pieces, then pat the pieces with a paper towel to remove all of the juice. Sprinkle cherries evenly over the top of the cake batter. Bake at 350 degrees for 30-35 minutes or until an inserted toothpick comes out clean.
While the cake is baking, in a 1 qt. saucepan combine the pineapple and juice with the sugar. Stir and bring to a boil, then immediately remove from heat and allow to sit on an unheated burner until the cake is done baking.
Remove cake from oven and immediately use a toothpick to poke holes all the way down through the cake -- make LOTS of holes. Spread the pineapple mixture over the top of the cake. Cool cake completely. Spread the Cool Whip over the top of the cake.
Spread the coconut on a cookie sheet and toast in the oven until the flakes are light brown. Let the coconut cool completely and sprinkle the coconut evenly over the top of the cake.