An Assertion Checking Wrapper Design for Java

The Java Modeling Language allows one to write formal behavioral specifications for Java classes in structured comments within the source code, and then automatically generate run-time assertion checks based on such a specification. Instead of placing the generated assertion checking code directly in the underlyling class bytecode file, placing it is a separate wrapper component offers many advantages. Checks can be distributed in binary form alongside the compiled class, and clients can selectively include or exclude checks on a per-class basis without recompilation. In this approach, when checks are excluded the underlying code is just as efficient as if assertions were “compiled out.” In addition, a flexible mechanism for enabling or disabling assertion execution on a per-class or per-package basis is also included. This paper presents a design for separating assertion checking code into wrapper classes and discusses the issues arising from this design.