A date-time without a time-zone _in the ISO-8601 calendar system, such as {@code 2007-12-03T10:15:30}. !(p) {@code LocalDateTime} is an immutable date-time object that represents a date-time, often viewed as year-month-day-hour-minute-second. Other date and time fields, such as day-of-year, day-of-week and week-of-year, can also be accessed. Time is represented to nanosecond precision. For example, the value "2nd October 2007 at 13:45.30.123456789" can be stored _in a {@code LocalDateTime}. !(p) This class does not store or represent a time-zone. Instead, it is a description of the date, as used for birthdays, combined with the local time as seen on a wall clock. It cannot represent an instant on the time-line without additional information such as an offset or time-zone. !(p) The ISO-8601 calendar system is the modern civil calendar system used today _in most of the world. It is equivalent to the proleptic Gregorian calendar system, _in which today's rules for leap years are applied for all time. For most applications written today, the ISO-8601 rules are entirely suitable. However, any application that makes use of historical dates, and requires them to be accurate will find the ISO-8601 approach unsuitable.