Difference between java HH:mm and hh:mm on SimpleDateFormat

Question

Whats the difference between kk:mm, HH:mm and hh:mm formats ??

    SimpleDateFormat broken = new SimpleDateFormat("kk:mm:ss");     broken.setTimeZone(TimeZone.getTimeZone("Etc/UTC"));     SimpleDateFormat working = new SimpleDateFormat("HH:mm:ss");     working.setTimeZone(TimeZone.getTimeZone("Etc/UTC"));     SimpleDateFormat working2 = new SimpleDateFormat("hh:mm:ss");     working.setTimeZone(TimeZone.getTimeZone("Etc/UTC"));      System.out.println(broken.format(epoch));     System.out.println(working.format(epoch));     System.out.println(working2.format(epoch)); 

prints:

24:00:00 00:00:00 05:30:00 

Answer 1

kk: (01-24) will look like 01, 02..24.

HH:(00-23) will look like 00, 01..23.

hh:(01-12 in AM/PM) will look like 01, 02..12.

so the last printout (working2) is a bit weird. It should say 12:00:00 (edit: if you were setting the working2 timezone and format, which (as kdagli pointed out) you are not)

Answer 2

Please take a look here

HH is hour in a day (starting from 0 to 23)

hh are hours in am/pm format

kk is hour in day (starting from 1 to 24)

mm is minute in hour

ss are the seconds in a minute