Modular Transformation of Java']Java Exceptions Modulo Errors

Deductive verifiers are used more and more in both academia and industry to prevent costly bugs. Their capabilities of verifying concurrent programs are getting better, but they are still lagging behind with regard to many major programming language features such as exceptions. To improve the situation, this work presents a semantics of Java exceptions which reduces the annotation burden on the user, while still allowing verification of exceptions. This is accomplished by ignoring sources of errors which are irrelevant to functional verification. Additionally, to deal with the complex control flow introduced by finally, a transformation is proposed that simplifies verification of exceptional postconditions and finally into postconditions and goto. We implement the approach and evaluate it against several common exception patterns.