Multiple calendar systems

Discussion of design issues around calendar systems

The JSR-310 API is built on the principle that the primary calendar system in the world is the ISO-8601 system. All key APIs, such a LocalDate and OffsetDateTime are built around this.

The rationale is that most developers use the de-facto civil calendar (ISO-8601) in the daily lives and in their coding lives. Almost all global business, network traffic and storage (databases) uses either ISO-8601 or a simple count from a fixed epoch (the Instant class in JSR-310).