Java DateTimeFormatterBuilder with optional pattern results in DateTimeParseException

Question

Goal

Provide a flexible parser for LocalDate instances that can handle input in one of the following formats:

• yyyy
• yyyyMM
• yyyyMMdd<

Answer 1

You set a value for month and day but pass a month and year. That's the problem.

You may want to use :

.parseDefaulting(ChronoField.MONTH_OF_YEAR, 1)
.parseDefaulting(ChronoField.YEAR_OF_ERA, ZonedDateTime.now().getYear())