OffsetDateTime format() method in Java with examples

The format() method of OffsetDateTime class in Java formats this date-time using the specified formatter.

Syntax : 

public String format(DateTimeFormatter formatter)

Parameter : This method accepts a single parameter formatter which specifies the formatter to use, not null.
Return Value: It returns the formatted date string, not null.
Exceptions: The function throws a DateTimeException that is when an error occurs during printing. 
Below programs illustrate the format() method:
Program 1 : 

Java

// Java program to demonstrate the format() method
import java.time.OffsetDateTime;
import java.time.format.DateTimeFormatter;

public class GFG {
    public static void main(String[] args)
    {

        // Parses the date1
        OffsetDateTime date1 = OffsetDateTime.parse("2018-12-12T13:30:30+05:00");

        // Prints the date
        System.out.println("Date1: " + date1);

        DateTimeFormatter formatter = DateTimeFormatter.ISO_TIME;
        System.out.println(formatter.format(date1));
    }
}

Output:

Date1: 2018-12-12T13:30:30+05:00
13:30:30+05:00

Program 2 : 

Java

// Java program to demonstrate the format() method
// Exceptions

import java.time.OffsetDateTime;
import java.time.format.DateTimeFormatter;

public class GFG {
    public static void main(String[] args)
    {
        try {
            // Parses the date1
            OffsetDateTime date1 = OffsetDateTime.parse("2018-13-12T13:30:30+05:00");

            // Prints the date
            System.out.println("Date1: " + date1);

            DateTimeFormatter formatter = DateTimeFormatter.ISO_TIME;
            System.out.println(formatter.format(date1));
        }
        catch (Exception e) {
            System.out.println(e);
        }
    }
}

Output:

java.time.format.DateTimeParseException: Text '2018-13-12T13:30:30+05:00' could not be parsed: Invalid value for MonthOfYear (valid values 1 - 12): 13

Reference: https://docs.oracle.com/javase/8/docs/api/java/time/OffsetDateTime.html#format-java.time.format.DateTimeFormatter-