I didn't say that a signed int would be fine. I said that a signed 64-bit int would be fine. Moreover, it is trivial to convert from a 32-bit signed or unsign

I didn't say that a signed int would be fine. I said that a signed 64-bit int would be fine. Moreover, it is trivial to convert from a 32-bit signed or unsigned type to a 64-bit int, so you are not constrained by the size type of Java.