This book offers experienced developers a good source for Real Time Specification for Java (RTSJ) that is compact, yet complete. The book examines the theoretical and practical aspects of RTSJ version 1.0.2 and provides many examples that have been effectively tested using the official Timesys Reference Implementation (RI), which can be obtained free, for noncommercial purposes [1].

Dibble has actively participated in RTSJ task forces--specifically, the Java Primary Expert Group and the Java Technical Interpretation Committee. He used this experience to synthesize the main features of RTSJ, in the 30 chapters of the book. The information he provides has enough detail to allow the reader to identify Java’s strengths as a platform for the development of real-time applications.

The first seven chapters review general concepts of real-time systems that provide a theoretical basis for RTSJ. Particularly important topics are priority scheduling, priority inversion, and scheduling with deadlines. Even for experienced readers, it is important to brush up on these concepts, as they are constantly referenced throughout the book, in order to complete important ideas.

Chapter 8 lists the six main enhancements to RTSJ, in relation to the Java standard specification. These basic guidelines relate to real-time threads, garbage collection, asynchronous event handlers, mechanisms for asynchronous transfer of control, and resources for addressing memory allocation of objects and for accessing physical memory positions. Starting with chapter 9, the information presented refers to these six main guidelines.

Dibble provides four helpful tutorials that enable the reader to put into practice the features of RTSJ, by using either RI or some other implementation. The tutorials teach various things, ranging from executing a basic “Hello World” program from a periodic or aperiodic real-time thread, using real-time priorities, to more complex applications that use, among other features, asynchronous event handlers, synchronization queues without blocking, real-time timers, immortal memory, and raw memory access. The author does not go into too much detail, but there is sufficient material about almost all of the critical subjects of RTSJ. The important chapters deal with real-time threads, asynchronous events, memory management and garbage collection, object synchronization, reusing objects, and accessing the physical memory; they give the reader a comprehensive idea about RTSJ’s capabilities. One exception is perhaps the chapter on scheduling, as it does not address the relationship between the fixed-priority preemptive scheduler of a real-time Java Virtual Machine (JVM) and its host operating system’s scheduler.

Throughout the book, Dibble offers practical advice on applying the real-time enhancements and addresses the interaction of Java’s standard resources with those from RTSJ, such as ordinary threads with real-time threads. The last chapter is quite useful; it includes a compendium of RTSJ features and a quick guide of recommendations on how to apply them correctly.

This book is an important contribution to the real-time and embedded applications literature. It shows the viability of Java as a reliable platform for developing fast and portable real-time applications.