JavaServer Pages Standard Tag Library
The JSP Standard Tag Library (JSTL) is a premade tag library standardized through the Java Community Process that consists of numerous custom tags commonly required by JSP authors. JSTL includes tags for conditionals and iterators (see Listings Three and Four), internationalization and formatting, XML document manipulation, internationalization and formatting based on locales, SQL, and more. JSTL 1.1 supports the same expression language as JSP 2.0, and also provides an API you can use to programmatically configure JSTL tags and create custom tags that are in line with JSTL conventions. Although JSTL isn't a required part of either JSP 2.0 or J2EE 1.4, it is highly recommended for anyone serious about JSP development and will likely be built into forthcoming JSP 2.0 containers. Apache Tomcat 5, for example, supports JSTL "out of the box," as I suspect most JSP 2.0 containers and J2EE 1.4 environments will when such products begin to ship later this year. For more details, see http://java.sun.com/products/jsp/jstl/.