I want to record the time using System.currentTimeMillis() when a user begins something in my program. When he finishes, I will subtract the current Syste
Shortest solution:
Here's probably the shortest which also deals with time zones.
System.out.printf("%tT", millis-TimeZone.getDefault().getRawOffset());
Which outputs for example:
00:18:32
Explanation:
%tT is the time formatted for the 24-hour clock as %tH:%tM:%tS.
%tT also accepts longs as input, so no need to create a Date. printf() will simply print the time specified in milliseconds, but in the current time zone therefore we have to subtract the raw offset of the current time zone so that 0 milliseconds will be 0 hours and not the time offset value of the current time zone.
Note #1: If you need the result as a String, you can get it like this:
String t = String.format("%tT", millis-TimeZone.getDefault().getRawOffset());
Note #2: This only gives correct result if millis is less than a day because the day part is not included in the output.