Originally posted by Ulf Dittmer:
TagSupport is not -and has never been- part of servlet-api.jar; it's in jsp-api.jar
Perhaps the point of confusion is that, prior to Tomcat 5, the servlet and JSP APIs were both bundled into the same jar file.
However, anyone who is writing web applications should have a copy of the Servlet and JSP specifications handy, in which case it would be quite clear that even though the SimpleTag mechanism has been added with JSP 2.0, that the "classic" tag handling mechanism provided by Tag and TagSupport is still available.