Towards a Revision of the Single Parent Rule in Real-Time Java, Maintaining the RTSJ Programming Model

The memory model used in the Real-Time Specification for Java (RTSJ) offers real-time guaranties to time-critical tasks by tuning of the Garbage Collector, providing as alternative to the garbage collected heap immortal and scoped memory regions. In order to avoid cycles among objects allocated within different scoped memory regions, the single parent rule guarantees that once a real-time thread has entered a set of scoped regions in a given order, any other realtime thread will have to enter them in the same order. This rule introduces race carrier condition in RTSJ program execution. This paper addresses two solutions to this problem that are compliant with the RTSJ programming model.