I was using a java.lang.Double as the return value for one of my overlay objects, and it was fine until I tried to do any math on it. Nothing would seem to turn the value into a Double or a double, yet no exceptions were thrown. After some sleuthing in web mode, it turned out that the value returned when I was trying to parse it was NaN, even though when I output it to the screen, the value looked like a double. I guess it was being treated as a
Easily enough fixed, just make sure that you don’t use any objects wrappers of primitives in an overlay type.