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 Polychrony, 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 optimizatio...