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A Machine-Checked Model for a Java-Like Language, Virtual Machine and Compiler

December 1, 2005

  • Date: Thursday, December 1st, 2005
  • Time: 11:00-12:15pm. 
  • Place: Woodward 149

Prof. Dr. Tobias Nipkow Department of Informatik Technical University of Munich Germany

We introduce Jinja, a Java-like programming language with a formal semantics designed to exhibit core features of the Java language architecture. Jinja is a compromise between realism of the language and tractability and clarity of the formal semantics. The following aspects are formalised: a big and a small step operational semantics for Jinja and a proof of their equivalence; a type system and a definite initialisation analysis; a type safety proof of the small step semantics; a virtual machine (JVM), its operational semantics and its type system; a type safety proof for the JVM; a bytecode verifier, i.e. data flow analyser for the JVM; a correctness proof of the bytecode verifier w.r.t. the type system; a compiler and a proof that it preserves semantics and well-typedness.

The emphasis of this work is not on particular language features but on providing a unified model of the source language, the virtual machine and the compiler. The whole development has been carried out in the theorem prover Isabelle/HOL jointly with Gerwin Klein.

The talk will give a very high-level overview of these formalizations. Full paper available at