What is Motorola Camera app's Photo naming convention? The Images are saved as IMG_yyyyMMdd_kkmmssSSS.jpg

Here, the yyyyMMdd part in filenames matches the first half of the photo's EXIFDate/Time data. 

Can anyone please help me out with figuring out the rest of the file name and how can I extract this from the photo's EXIF data?
The format follows the pattern used in DateFormat class from Java/Android. It's:


IMG: constant prefix for Images
yyyyMMdd: date


years (4-digit)
months (2-digit)
days (2-digit)

kkmmssSSS: time


hours (2-digit in 24-hour format, from 1-24)
minutes (2-digit)
seconds (2-digit)
milliseconds (3-digit)