What Is the Java Date and Time API?

Java added a new Date and Time API in Java 8 version that consists of several classes, interfaces, and enum to handle the date and time.

Before Java 8, There was a java.util.Date class to create and handle date and time that has limitations like Not thread-safe, Poor design, and Difficult time zone handling.

The new Date and Time API is based on the ISO calendar system and all the classes are immutable and thread-safe.

The classes of java.time package represent the principle date-time concepts, including instants, durations, dates, times, time-zones, and periods.

The new java.time package includes the various classes and enums that are tabled below.

The following are the Enum present in java.time package.

This class is available in java.time package. It represents a date without a time-zone in the ISO-8601 calendar system, such as 2007-12-03.

The LocalDate class is an immutable date-time object that is used to create a locale date. See the below example.

public class STDemo {
    public static void main(String[] args){
        
        LocalDate date = LocalDate.parse("2012-12-10");
        System.out.println(date);    
    }
}

Output:

2012-12-10

This class is used to create a date with time but without a time-zone. It represents a date-time without a time-zone in the ISO-8601 calendar system, such as 2010-10-03T10:10:50.

The LocalDateTime class is an immutable date-time object that represents a date-time. We can use it to represent a date with time. For example, the value "2nd October 2007 at 13:45.30.123456789" can be stored in a LocalDateTime.

import java.time.LocalDateTime;

public class STDemo {
    public static void main(String[] args){
        
        LocalDateTime date = LocalDateTime.of(2012, 12, 10, 2, 30);
        System.out.println(date);    
    }
}

Output:

2012-12-10T02:30

This class is used to create a local time object. It represents a time without a time-zone in the ISO-8601 calendar system, such as 11:10:30.

The LocalTime class is an immutable date-time object that represents a time, For example, the value "13:45.30.123456789" can be stored in a LocalTime. See the below example.

import java.time.LocalTime;

public class STDemo {
    public static void main(String[] args){
        
        LocalTime time = LocalTime.of(12, 12,30);
        System.out.println(time);    
    }
}

Output:

12:12:30

This class is used to create a date-time object with a time-zone. It represents a date-time with a time-zone in the ISO-8601 calendar system, such as 2017-10-03T10:10:30+05:30 Asia/Kolkata.

The ZonedDateTime class is an immutable representation of a date-time with a time-zone. This class stores all date and time fields. For example, the value "2nd October 2017 at 15:40.35.123456786 +05:30 in the Asia/Kolkata time-zone" can be stored in a ZonedDateTime.

import java.time.ZoneId;
import java.time.ZonedDateTime;

public class STDemo {
    public static void main(String[] args){
        
        ZonedDateTime time = ZonedDateTime.of(2015, 10, 15, 2, 10, 30, 0, ZoneId.systemDefault());
        System.out.println(time);    
    }
}

Output:

2015-10-15T02:10:30+05:30[Asia/Kolkata]

This class is used to create a date-time with an offset from UTC/Greenwich in the ISO-8601 calendar system, such as 2017-10-03T15:10:30+01:00.

The OffsetDateTime class is an immutable representation of a date-time with an offset. This class stores all date and time fields, as well as the offset from UTC/Greenwich. For example, the value "2nd October 2017 at 15:42.35.123456789 +02:00" can be stored in an OffsetDateTime.

import java.time.OffsetDateTime;
public class STDemo {
    public static void main(String[] args){
        
        OffsetDateTime date = OffsetDateTime.parse("2017-02-03T12:30:30+01:00");
        System.out.println(date);
    }
}

Output:

2017-02-03T12:30:30+01:00

This class is used to store time with an offset from UTC/Greenwich in the ISO-8601 calendar system, such as 15:10:35+01:00.

The OffsetTime class is an immutable date-time object that represents a time. This class stores all time fields, as well as a zone offset. For example, the value "15:40.35.123456789+02:00" can be stored in an OffsetTime.

import java.time.OffsetTime;
public class STDemo {
    public static void main(String[] args){
        
        OffsetTime time = OffsetTime.parse("12:30:30+01:00");
        System.out.println(time);
    }
}

Output:

12:30:30+01:00