[Java] Calculate the angle between clock hands

return null;

Unless it's an analog clock, in which case:

The hour hand makes a 360 degree turn every 12 hours or 12*60 = 720 minutes, therefore each minute the hand moves 360/720 = 0.5 degrees

The minute hand makes a 360 degree turn every hour or 60 minutes, therefore each minute the hand moves 360/60 = 6 degrees

Setting 12 as the 0 position, to calculate the angle of each hand we can:

•     hours = 0.5 * current minutes for that hour (60 * hours + minutes)
•     minutes = 6 * minutes

We now have the position of both hand with respect to the 12 o'clock, the angle between them will simply be the difference, between the two positions (absolute value!)

If the difference is more than 180 degrees, the angle is a reflex angle and since we want the smallest angle between the hands, we take its complement by subtracting it from 360 (again, absolute value unless we did a modulo before to account for 24 hour format)

You can check my implementation of clockAngle on my Gist along with some tests in ClockAngleJTests.