Toward a Unified Standard for Worst-Case Execution Time Annotations in Real-Time Java

As real-time systems become more prevalent, there is a need to guarantee that these increasingly complex systems perform as designed. One technique involves a static analysis to place an upper bound on worst-case execution time (WCET). This temporal analysis cannot be made automatic and normally requires source annotations to assist a WCET analysis tool. At the same time, there is a growing interest in using Java for real-time systems. Several WCET analysis prototypes for Java have been created, and more are under development. Each relies on a competing and incompatible convention for annotations, resulting in portability problems and duplication of effort. We propose that Java's own annotation mechanism should be used to address such issues. These built-in annotations provide a common platform for WCET analysis, improving portability and reducing the effort necessary to create these vital tools. We examine the features that make Java's annotation standard attractive for WCET analysis, then discuss its current failings and make recommendations for future improvements.