From object-oriented code with assertions to behavioural types

The widespread use of service-oriented and cloud computing is creating a need for a communication-based programming approach to distributed concurrent software systems. Protocols play a central role in the design and development of such systems but mainstream programming languages still give poor support to ensure protocol compatibility. Testing alone is insufficient to ensure it, so there is a pressing need for tools to assist the development of these kind of systems. While there are tools to verify statically object-oriented code equipped with assertions, these mainly help to prevent runtime errors. However, a program can be ill-behaved and still execute without terminating abruptly. It is important to guarantee that the code implements correctly its communication protocol. Our contribution is a tool to analyse source code written in a subset of Java, equipped with assertions, and return it annotated with its respective behavioural types that can be used to verify statically that the code implements the intended protocol of the application. A running example illustrates each step of the tool.