Difference between Calendar.HOUR and Calendar.HOUR_OF_DAY?

Question

What is the difference between Calendar.HOUR and Calendar.HOUR_OF_DAY ? When to use Calendar.HOUR and Calendar.HOUR_OF_DAY

Answer 1

From http://docs.oracle.com/javase/7/docs/api/java/util/Calendar.html#HOUR:

Calendar.HOUR = Field number for get and set indicating the hour of the morning or afternoon. HOUR is used for the 12-hour clock. E.g., at 10:04:15.250 PM the HOUR is 10.

Calendar.HOUR_OF_DAY = Field number for get and set indicating the hour of the day. HOUR_OF_DAY is used for the 24-hour clock. E.g., at 10:04:15.250 PM the HOUR_OF_DAY is 22.