Résumé
The popular slogan “write once, run anywhere” effectively renders the expressive capabilities of the JAVA programming framework for developing, deploying, and reusing target-independent applets. Its generality and simplicity has driven most attention of the compiler technology community to developing just-in-time and runtime compilation techniques, local and compositional optimization algorithms. When it comes to real-time JAVA and to the implementation of embedded software, this approach is however far from satisfactory, especially in hard real-time system design (e.g. airborne systems) where conformance to real-time specifications is critical. We show that synchronous design tools, and particularly the design workbench POLYCHRONI, allow for a complete modeling of embedded software written in a high-level and general purpose programming language such as JAVA. The synchronous approach provides a formal engineering model and methodology, using global transformation and optimization techniques, that allow for a JAVA program written once to be mapped on any distributed target architecture. We present a technique to import a resource constrained, multi-threaded, RT JAVA program, together with its runtime system API, into POLYCHRONI. We put this modeling technique to work by considering a formal, refinement-based, design methodology that allows for a correct by construction remapping of the initial threading architecture of a given JAVA program on either a single-threaded target or a distributed architecture. This technique allows to generate stand-alone (Jvm-less) executables and to remap threads onto a given distributed architecture or a prescribed target real-time operating system. As a result, it allows for a complete separation between the virtual threading architecture of the functional-level system design (in JAVA) and its actual, real-time and resource constrained implementation.