Coin

Represents an amount of Cardano's native currency (ADA)

On the wire a coin is unsigned (Conway CDDL coin = uint), and the CBOR decoder rejects negative values. The constructor deliberately allows negative amounts: balancing and Value arithmetic produce transient negative differences.

Arithmetic throws ArithmeticException when the result does not fit in a Long, rather than wrapping around: a wrapped sum would be a wrong amount.