[michaelt]

One risk with a bigger standard library is that you'll do an imperfect job of it, then you'll be stuck maintaining it forever for compatibility reasons.

For example, Java developers can choose to represent time with Unix milliseconds, java.util.Date, java.util.Calendar, Joda-Time or java.time.Instant

[layer8]

It’s really just Date and Instant. Joda-Time isn’t part of the standard library. And if you’re listing Calendar, you might as well also list ZonedDateTime, OffsetDateTime, and LocalDateTime, not to mention stuff like java.sql.Date.

In reality, there’s just one old API and one new API, similar to the old collection classes (HashTable, Vector, etc.) and the newer JCF ones.