Java XML and JSON can be used as both a self-study guide and a reference for Extensible Markup Language (XML) and JSON documents and their processing in Java. The book is ideal for Java programmers needing to develop applications that read, write, or translate either format. No particular background on XML, XSLT, or JSON is assumed or required.

Readers will get a good understanding of the basic language concepts as well as a working knowledge of parsing methods for hierarchical documents. Each chapter is concisely written and has plenty of code examples (which can be downloaded and run), as well as implementation notes, a review test, and a summary.

The first part of the book covers in detail XML-related technologies, like XML documents, XML schema, document type definitions (DTDs), and XSLT, starting from basic language features.

XML parsing with stream and tree-based methods using SAX, the document object model (DOM), and StAX (the streaming application programming interface (API) for XML) are also exemplified in Java code, as is XPATH, the traversal query language for XML documents. Advanced XPATH features like user-defined functions and variables are also shown.

The discussion of JSON in the second half of the book should be easy to follow once the reader has gone through the XML chapters. Given that a JSON document is much simpler than XML and can be viewed as a JSON object with nested JSON objects and arrays, the same XML parsing techniques (streaming, tree-based) apply. The code examples use either mJson or Gson, but the same principles can be extrapolated to other popular libraries like Jackson or json4j. The final discussion and examples on JsonPath should also be familiar to readers that have worked out the examples on XPATH in chapter 5.

In summary, Java XML and JSON is an efficient, practical guide for developers, providing the background to write applications to process and query complex documents in a little over 200 pages, most of which are devoted to code examples.