A Locale object represents a specific geographical, political, or cultural region. It represents a language/country/variant combination. Locales are used to alter the presentation of information such as numbers or dates to suit the conventions in the region. Date and time are locale-sensitive, because they are written differently in different parts of the world. You will use the method Locale.getDefault() to retrieve the locale information set on the user's device and pass it into the SimpleDateFormat constructor.
SimpleDateFormat is a concrete class for formatting and parsing dates in a locale-sensitive manner.
It allows for formatting (date -> text), parsing (text -> date), and normalization.
val formatter = SimpleDateFormat("E MMM d", Locale.getDefault())Use Calendar only as a calculator which, when given Date and TimeZone objects, will do calculations for you. Avoid its use for property typing in an application.
Date is best for storing a date object. It is the persisted one, the Serialized one.
Calendar is best for manipulating Dates.
Dates should be used as immutable points in time; Calendars are mutable, and can be passed around and modified
Date does not have a notion of timezone.
Date and Calendar are really the same fundamental concept (both represent an instant in time and are wrappers around an underlying long value - time since jan 1 1970).
Dates should be used as immutable points in time; Calendars are mutable, and can be passed around and modified
java.time.LocalDate : represents a year-month-day in the ISO calendar and is useful for representing a date without a time. It can be used to represent a date only information such as a birth date or wedding date.
E.g.
System.out.println(LocalDate.now());// 2022-07-05java.time.LocalTime : deals in time only. It is useful for representing human-based time of day, such as movie times, or the opening and closing times of the local library.
java.time.LocalDateTime : handles both date and time, without a time zone. It is a combination of LocalDate with LocalTime.
java.time.ZonedDateTime : combines the LocalDateTime class with the zone information given in ZoneId class. It represent a complete date time stamp along with timezone information.
java.time.OffsetTime : handles time with a corresponding time zone offset from Greenwich/UTC, without a time zone ID.
java.time.Clock : provides access to the current instant, date and time in any given time-zone. Although the use of the Clock class is optional, this feature allows us to test your code for other time zones, or by using a fixed clock, where time does not change.
java.time.Instant : represents the start of a nanosecond on the timeline (since EPOCH) and useful for generating a timestamp to represent machine time. An instant that occurs before the epoch has a negative value, and an instant that occurs after the epoch has a positive value.
java.time.Duration : Differnce between two instants and measured in seconds or nanoseconds and does not use date-based
constructs such as years, months, and days, though the class provides methods that convert to days, hours, and minutes.
java.time.Period : To define the difference between dates in date-based values (years, months, days).