Supporting Mixed Criticality Applications in a Ravenscar-Java Environment

Ravenscar-Java is a subset of Java augmented by a subset of the Real-Time Specification for Java. It is targeted at high integrity real-time systems, however, currently only a single integrity level is supported. This paper proposes extensions to Ravenscar-Java to allow it to support multiple criticality applications within the same virtual machine on a single processor. A real-time isolate is defined which supports both temporal and spatial firewalling. Communication mechanisms are provided to allow controlled interaction between high and low-level integrity applications. The implementation in a Ravenscar-Java environment is discussed. Byte code verification and analysis is performed offline to ensure the robust, predictable, scalable, efficient and safe execution of Ravenscar-Java applications. A temporal deterministic runtime architecture of the Ravenscar-Java is proposed to achieve temporal and spatial isolation between applications, and also improve the scalability by safely sharing the runtime data structures as much as possible with the help of the offline analyzer.