Servlet API by tomcat

The javax.servlet.jsp package contains a number of classes and interfaces that describe and define the contracts between a JSP page implementation class and the runtime environment provided for an instance of such a class by a conforming JSP container.

The JavaServer Pages(tm) (JSP) 2.0 specification provides a portable API for evaluating "EL Expressions". As of JSP 2.0, EL expressions can be placed directly in the template text of JSP pages and tag files.

This package contains a number of classes and interfaces that describe and define programmatic access to the Expression Language evaluator. This API can also be used by an implementation of JSP to evaluate the expressions, but other implementations, like open-coding into Java bytecodes, are allowed. This package is intended to have no dependencies on other portions of the JSP 2.0 specification.

The JavaServer Pages(tm) (JSP) 2.0 specification provides a portable mechanism for the description of tag libraries.

A JSP tag library contains

• A Tag Library Descriptor
• A number of Tag Files or Tag handler classes defining request-time behavior
• Additional classes and resources used at runtime
• Possibly some additional classes to provide extra translation information

The JSP 2.0 specification and the reference implementation both contain simple and moderately complex examples of actions defined using this mechanism. These are available at JSP's web site, at http://java.sun.com/products/jsp. Some readers may want to consult those to get a quick feel for how the mechanisms work together.