Other than unsigned types for FFI or wire formats (which Java supports just fine) or for bitfields (which Java doesn't have), what do you want unsigned numerics

Other than unsigned types for FFI or wire formats (which Java supports just fine) or for bitfields (which Java doesn't have), what do you want unsigned numerics for? The risk of unsigned types (even without the C or C++ issues around mixing with signed types) is that too many people make the mistake of using them to express the invariant of "a number that must be positive", which modular arithmetic types are a really bad fit for. One possible use is for a memory-efficient storage of small positive values, say in a byte. But then you have to make a choice between forcing the value into a signed type for arithmetic (which Java easily lets you do with Byte.toUnsignedInt) and allowing signed and unsigned types to be mixed.