Safety-critical Java for embedded systems

This paper presents the motivation for and outcomes of an engineering research project on certifiable Java for embedded systems. The project supports the upcoming standard for safety-critical Java, which defines a subset of Java and libraries aiming for development of high criticality systems. The outcome of this project include prototype safety-critical Java implementations, a time-predictable Java processor, analysis tools for memory safety, and example applications to explore the usability of safety-critical Java for this application area. The text summarizes developments and key contributions and concludes with the lessons learned

From Java to real-time Java : A model-driven methodology with automated toolchain

Real-time systems are receiving increasing attention with the emerging application scenarios that are safety-critical, complex in functionality, high on timing-related performance requirements, and cost-sensitive, such as autonomous vehicles. Development of real-time systems is error-prone and highly dependent on the sophisticated domain expertise, making it a costly process. There is a trend of the existing software without the real-time notion being re-developed to realise real-time features, e.g., in the big data technology. This paper utilises the principles of model-driven engineering (MDE) and proposes the first methodology that automatically converts standard time-sharing Java applications to real-time Java applications. It opens up a new research direction on development automation of real-time programming languages and inspires many research questions that can be jointly investigated by the embedded systems, programming languages as well as MDE communities

A Foundation for Development of Programming Languages for Real-Time Systems

Applications of real-time systems have grown considerably in both diversity and popularity, and the demand for real-time software has never been higher. In contrast, the choice of programming languages used to develop these systems has mostly remained limited to decades-old languages, namely Ada and C/C++, and more recently real-time Java. We postulate that the main reason for this mono-culture is the difficulty of developing new programming languages for real-time systems, due to their strict correctness requirements. Wang et al. argue that implementing even general-purpose languages is not easy, and is the source of many problems in today's languages. They propose the Micro Virtual Machine as a minimal abstraction layer to relieve the challenges of implementing a managed language, and design a micro VM specification named Mu. Compared to conventional language VMs, a micro VM is minimal and low-level. This makes micro VM an appealing idea towards creating a platform for development of programming languages for real-time systems, as it allows supporting a wide range of languages, aligned with the huge diversity of real-time systems. It also makes correct implementation and formal verification of the platform easier, which is vital for many real-time systems. Prior to this thesis, the only concrete micro VM specification was [Mu, 2018]. However,Mu is not designed for real-time systems and lacks some of the essential features. My thesis is that a real-time-enabled micro virtual machine is capable of providing an efficient and usable foundation for development of program-ming languages, suitable for building real-time software. The first high-level contribution of this thesis is the design of RTMu, a micro VM instance aiming at programming languages for real-time systems. We build on the Mu specification and propose a set of modifications to its abstractions over concurrency and memory management to make it suitable for real-time systems. The second contribution is the affirmation of the implementability of the RTMu's abstractions. For this purpose, we build a high-performance implementation of the RTMu specification, based-on a high-performance implementation of Mu. The third contribution is the design of a real-time extension to RPython, to make it a fully-featured language for real-time systems, named RT-RPython. We implement RT-RPython on top of RTMu and evaluate its performance through the CollisionDetection benchmark suite. This thesis is a proof of concept for establishing the use of micro VMs to build new high-quality programming languages for real-time systems. It also provides empirical demonstration of performance and predictability for micro VMs in the real-time domain. We believe that RTMu can help in tackling the current lack of diversity in programming languages for real-time systems