Treffer: Verified Bytecode Verification and Type-Certifying Compilation

This article presents a type certifying compiler for a subset of Java and proves the type correctness of the bytecode it generates in the proof assistant Isabelle. The proof is performed by defining a type compiler that emits a type certificate and by showing a correspondence between bytecode and the certificate which entails welltyping. The basis for this work is an extensive formalization of the Java bytecode type system, which is first presented in an abstract, lattice-theoretic setting and then instantiated to Java types.