There you have it -- the making of a robust, scalable, and powerful compute engine. You learned about Jini transactions previously and how they provide a general and powerful model for building robust distributed applications. In this article, you've seen how to incorporate transactions into a fairly sophisticated application so that it will operate in a safe and correct manner in the presence of partial failure. You've also seen one way an application might make use of multiple spaces in order to become more truly scalable. With this information in hand, you should be well equipped to build your own applications that are fault tolerant and scalable.
About the Author
Dr. Susanne Hupfer is director of product development for Mirror Worlds Technologies, a Java- and Jini-based software applications company, and a research affiliate in the department of computer science at Yale University, where she completed her Ph.D. in space-based systems and distributed computing. Previously, she taught Java network programming as an assistant professor of computer science at Trinity College. Susanne coauthored the Sun Microsystems book JavaSpaces Principles, Patterns, and Practice.
For a more in-depth exploration of space-based programming concepts and code examples, as well as a detailed look at the JavaSpaces technology APIs, refer to Sun's official Jini Technology Series book on the topic: JavaSpaces Principles, Patterns, and Practice, Eric Freeman, Susanne Hupfer, and Ken Arnold (Addison-Wesley, 1999): http://www.amazon.com/exec/obidos/ASIN/0201309556/
For specifics on Jini transactions, see The Jini Specification -- another Jini Technology Series book -- by Ken Arnold, Bryan O'Sullivan, Robert W. Scheifler, Jim Waldo, and Ann Wollrath (Addison-Wesley, 1999): http://www.amazon.com/exec/obidos/ASIN/0201616343/
You'll also find more information on Jini transactions in Core Jini by W. Keith Edwards (Prentice-Hall, 1999). This book provides in-depth treatment of Jini, including information about lookup and discovery: http://www.amazon.com/exec/obidos/ASIN/013014469X/
Whether you wish to share information with other developers (including the Sun engineers that developed the Jini and JavaSpaces technologies), or to seek troubleshooting advice, the official JavaSpaces-users mailing list is the place to go: http://archives.java.sun.com/archives/javaspaces-users.html