Javalight is type-safe - definitely

Abstract

Javalight is a large sequential sublanguage of Java. We formalize its abstract syntax, type system, well-formedness conditions, and an operational evaluation semantics. Based on this formalization, we can express and prove type soundness. All definitions and proofs have been done formally in the theorem prover Isabelle/HOL. Thus this paper demonstrates that machine-checking the design of non-trivial programming languages has become a reality.