Tag handler

Tag Files are just about including a JSP fragment in a JSP page.

Tag handlers, on the other side, make available Java code to a JSP page.

Tag handlers are available in two flavors:

Classic tag handlers - required for compatibility and somehow more powerful, are more difficult to develop and maintain.

Simple tag handlers - available from JSP 2.0

Tag handlers are discussed in chapter ten of Head First Servlet and JSP.