Same for C#. Any narrowing truncation needs to be an explicit cast. Widening is typically allowed implicitly, although in the case of the 'decimal' (128 bit struct representing a 'higher precision' floating point) type you still need an explicit cast from a 'double', since there are cases where that conversion can still change the value or fail (i.e. Infinity/NaN)

Microsoft is considering turning on by default checked arithmetic in the 2022 Visual Studio templates, by the way.

It can catch people by surprise that Java's narrowing conversions may not preserve the sign. For example, the following is broken:

class TimestampedObject implements Comparable<TimestampedObject> { long timestamp; int compareTo(TimestampedObject other) { return (int)(timestamp - other.timestamp); } ... }

ErrorProne catches this: https://errorprone.info/bugpattern/BadComparable

Noo! This idea is super new and was invented by Go/Rust.