8.9. The JSP Standard Tag Library (JSTL)

The intent of the early JSP specification group members was to define a set of standard JSP tags within the specification. This would allow vendors to generate their own versions of the standard tags but also allow developers to count on this set of standard tags to be available in all compliant containers. However, due to time constraints, that feature of the early JSP specification was not included.

Since then, many vendors have created their own versions of commonly used tag libraries, but these versions are different enough that developers can't easily port their JSP pages from one container to another without having to modify the pages. JSR 52, the JSP Standard Tag Library (JSTL), aims to fix that problem.