The front cover of this book states that it 'covers cryptographic techniques for secure Internet applications', which is indeed born out by the volume of content relating to security issues. For example, the first of this book's five sections contains a brief description of basic networking terms (relating to the common Internet protocols, name lookup and firewalls, etc.) together with an introduction to general cryptographic techniques and the security model of JAVA.
The second and largest section covers the JAVA networking APIs. The various stream classes are introduced and then extended and linked together to produce some required higher level functionality.
Half of the third section uses the new classes created previously to build a multi-user chat application for both the server and client. The other half of this section further extends previously created classes to provide secure transactions, using encrypted data streams and user authentication.
The last sections outline other related APIs that will be found in version 1.1 of the JDK (as this book is predominantly based on version 1.02) together with appendices that provide additional information and further reading pointers for general networks (LANs, WANs, etc.) and cryptography.
The book contains many useful code snippets and diagrams with the full code available on the enclosed CD-ROM. There are also many textual definitions of the class methods being used (sometimes covering several pages) which, whilst sometimes useful often were too brief for a true definition but long enough to get in the way of the topic at hand. I also found that the same informationwas often given in adjacent paragraphs, especially in the first two sections. Maybe this was due to the number of authors involved but was at times very off-putting.
Aside from the sentence repetitions early on, the book introduces the JAVA stream APIs well, with useful and meaningful extensions culminating in a simple chat system. Also welcome is the recognition and effort given to security related issues.