6.

  

THE BUSINESS AND ACADEMIC WORLDS HAVE LONG ACCEPTED the use of networking technologies, allowing users to share files and applications and to exchange information using network services such as email. The explosive growth of the Internet has made everyone conscious of the importance of networked applications, and this importance is set to grow at an enormous rate with the emergence of home and mobile networks.

For the programmer, building distributed applications can be a complex business. There are issues related to network stability and accessibility in addition to partitioning applications into portions that can run separately but still be linked into larger functional units. A large variety of frameworks-experimental and commercial-have been devised to make it easier to build and deploy distributed applications.

Jini is one of the latest frameworks for building distributed applications. Created by Sun Microsystems, it builds upon previous experiences but also introduces new concepts that fit into the modern object-oriented world. Jini is written in Java and distributes and organizes applications based on the distributed object-oriented principles supported by Java. It allows the programmer to build type-safe applications with distributed garbage collection, which results in applications that are resilient to network failures and can that discover and use distributed services at need.

This book is written for programmers/ architects who have a working knowledge of Java and of network programming and who want to come up to speed with Jini quickly. It assumes you are comfortable with network concepts such as remote procedure calls, are familiar with Java syntax, and have a working knowledge of the Java core classes.

This is a hands-on, study-the-code book. My intention is to introduce you to code that can be readily understood , and that can be copied and used in your own programs. The book covers the full range of Jini concepts, and it also deals with a number of advanced topics such as linking Jini and CORBA systems and using Jini to make hardware devices available across the network. The book has been available on the Internet in various forms for nearly two years , and has benefited from user feedback while it has been aiding many new Jini programmers.

The first eight chapters cover the basics of Jini programming, leading to a complete, but simple, application. The subsequent chapters discuss more advanced material, such as event handling, security, transactions, and activation, and it also covers the new helper classes of Jini 1.1. In addition, I have included topics not normally covered in Jini books, such as user interfaces, links to other distributed systems such as CORBA, and using hardware devices with Jini.

The book uses Jini version 1.1, released late in 2000, and the code works with both JDK 1.2 and JDK 1.3

Files

The source for the programs in the book is available as a zip file: programs.zip . The compiled classes are also available as a zip file: classes.zip . These files are on this Web site: http://pandonia.canberra.edu.au/java/jini/tutorial/Jini.xml .