Preventing signedness errors in numerical computations in Java

Abstract

We have developed and implemented a type system, the Signedness Type System, that captures usage of signed and unsigned integers in Java programs. This type system enables developers to detect errors regarding unsigned integers at compile time, and guarantees that such errors cannot occur at run time. In a case study. our type system proved easy to use and detected a previously unknown bug. Our type system is implemented as the Signedness Checker and will be available with the Checker Framework (http://CheckerFramework.org/).