What is the difference between map() and flatMap() in Optional?

Q: What is the difference between map() and flatMap() in Optional?

map(Function<T, R>) — Transforms the value inside Optional if present. Returns Optional<R>. If the function returns a value, it's wrapped in Optional. If the function returns null, returns Optional.empty().

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Accepted Answer

map(Function) — Transforms the value inside Optional if present. Returns Optional. If the function returns a value, it's wrapped in Optional. If the function returns null, returns Optional.empty().