JSP EL is a simple expression language for accessing data.

JSTL provides standard actions for functionality most often needed by page authors. This functionality includes a core library for the most common tasks, internationalization (i18n) and text formatting, relational database access (SQL), and XML processing.

JSP Directives control the processing of an entire page. Directive examples include setting a scripting language, setting an error page, including other sections, and setting a character encoding.

JSP makes implicit variables available to the script. These variables are used to gain information about the request, and to help form a response. They also expose some useful functionality.

Actions are the core of JSP. Actions range from printing a script expression, to creating and storing a Java Bean.

An application collects servlets, JSP pages, scripts and Java Beans into a self-contained web application. Applications are just generalized virtual hosts, only based on the URL instead of the host name.

The Apache Velocity project introduces an alternative syntax to the familiar JSP expressions and scriptlets. Resin's extension allows the use of Velocity-style syntax in JSP files. The Velocity-style syntax is transformed into JSTL standard tags.

The formal definition for the *.tld file