If you’ve read the second edition of JavaServer Pages, you’ll notice that, in this edition, even more of the custom components used in previous edition have been replaced in favor of the equivalent standard components from JSTL—–a specification I’ve been lucky enough to contribute to and help shape the standard based on many of the ideas explored in the first and second editions. You’ll also notice that all the chapters have been modified (some more than others) to cover the new features in the latest versions of the JSP and JSTL specifications. A brand new chapter has been added to describe how to develop custom tag libraries using the new tag file format, and the chapters about custom library development using Java has been substantially expanded to cover the new, simplified tag handler API as well as the new mechanism for including Expression Language functions in a tag library. All chapters have also been updated to cover the features and clarifications added in the Servlet 2.4 specification on which JSP 2.0 is based on. Here’s a brief summary of the primary changes in all the specifications covered in this book:

• Incorporation of the Expresssion Language (EL) (first introduced by the JSTL specification) in the JSP specification (making it available to all standard and custom components as well as in template text)
• The EL extended with a function call mechanism and a set of common functions added to JSTL.
• Addition of the ability to develop custom tag libraries as tag files (text files with JSP elements) as well as a new, simplified tag handler Java API, and various new tag library features such as support for a dynamic attribute list and executable fragment attributes.
• More flexible rules for JSP pages written as XML documents, and support for the the JSP directives and scripting elements XML syntax in regular JSP pages..
• New JSP standard elements, primarily to allow for more flexible attribute value assignments and to support the new tag file format and XML format enhancements.
• Access to more information in a JSP error page and adjustement of the attribute names to match the Servlet specification.
• Stricter container requirements to improve syntax error reporting and debugging support for JSP pages.
• XML Schema-based deployment descriptors for all specifications, with new configuration options, including automatic include of page segments, page encoding specification, scripting element disabling, and more for JSP.
• Addition of a new request listener component type and filters that can be applied to internal requests
• Deprecation of the single thread model for both servlets and JSP.
• New JSTL tag library URIs and a few attribute name changes for the XML library.