How to convert LocalDateTime to OffsetDateTime?

There are many ways to convert LocalDateTime to OffsetDateTime. Some of them are listed below:

1. Using LocalDateTime#atOffset​(ZoneOffset offset):

LocalDateTime ldt = LocalDateTime.now();
ZoneOffset offset = ZoneOffset.UTC;
OffsetDateTime odt = ldt.atOffset(offset);

2. Using LocalDateTime#atZone​(ZoneId zone) => ZonedDateTime#toOffsetDateTime():

LocalDateTime ldt = LocalDateTime.now();

// Change the ZoneId as required e.g. ZoneId.of("Europe/London")
ZoneId zoneId = ZoneId.systemDefault();

OffsetDateTime odt = ldt.atZone(zoneId).toOffsetDateTime();

3. Using OffsetDateTime#of​(LocalDateTime dateTime, ZoneOffset offset):

LocalDateTime ldt = LocalDateTime.now();
ZoneOffset offset = ZoneOffset.UTC;
OffsetDateTime odt = OffsetDateTime.of(ldt, offset);

4. ZonedDateTime#of​(LocalDateTime localDateTime, ZoneId zone) => ZonedDateTime#toOffsetDateTime():

LocalDateTime ldt = LocalDateTime.now();

// Change the ZoneId as required e.g. ZoneId.of("Europe/London")
ZoneId zoneId = ZoneId.systemDefault();

OffsetDateTime odt = ZonedDateTime.of(ldt, zoneId).toOffsetDateTime();

Notes:

1. In all the solutions given above, replace the sample ZoneOffset as required e.g. ZoneOffset offset = ZoneOffset.of("+02:00").
2. In all the solutions given above, replace the sample LocalDateTime as required e.g. LocalDateTime ldt = LocalDateTime.of(2021, 3, 14, 10, 20).