I use a chalky paint spray paint that will stick to glass well. Turn the jar upside down and paint from all directions. Let dry and voila!
If you paint the inside they’re still shiny on the outside. Plus it’s so easy. Pour a bit of any kind of paint in the jar and rotate the jar to reach up the sides. :)
Be sure to wipe the mason jar down well with an alcohol/water mix to get rid of any oils and fingerprints. Then simply spray like any other piece using several light coals rather than one thick one which often results in runs and drips. Spray from all angles to insure even coverage.
I add baking soda to my paint to make it chalky so it will stick to the glass.(1 part baking soda to 2 parts acrylic paint) Also, they make spray paint that will adhere to glass now. Check in the spray paint section at Walmart.