The Expression Language
One of the most important features in JSP 2.0 was the Expression Language (EL), which JSP authors can use to access application data. Inspired by both the ECMAScript and the XPath expression languages, the EL is designed to make it possible and easy to author script-free JSP pages, that is, pages that do not use JSP declarations, expressions, or scriptlets. (Chapter 17, “Model 2 and the MVC Pattern” explains why script-free JSP pages are considered good practice.)
The EL that was adopted into JSP 2.0 first appeared in the JSP Standard Tag Library (JSTL) 1.0 specification. JSP 1.2 programmers could use the language by importing the standard libraries into their applications. JSP 2.0 and later developers ...