Can Gel Stain be applied over a high gloss paint finish?
Possibly but not recommended - the high gloss is an issue. Folks have successfully put Gel Stain on more surfaces than we ever dreamed of including fiber glass but if you want to proceed, TEST your procedure on the inside of a door first, let the door cure for 14 days. Then further test the finish by duplicating normal wear and tear: washing, scrubbing, scratching, etc to see if the finish bonds to the surface. It might not adhere.
If you want to proceed with your project, the cabinets need to be sanded with 150-180 grit sandpaper before attempting to apply the Gel Stain. If you cannot achieve enough abrasion by sanding, apply a De-Glosser, available at any paint store. We think Milk Paint would be a better choice as paint is more flexible and tends to adhere well to many surfaces, but test to your satisfaction before proceeding. Milk Paint is available in Dark Chocolate, a very close color match to Java Gel.