Head First Servlets and JSP, 2nd Edition

Simple tags can have Classic parents

This is not a problem, because a SimpleTag’s getParent() returns type JspTag, and Classic tags and Simple tags now share the JspTag super interface. Actually, Classic tags can have Simple parents, but it takes a slight hack to make that work because you can’t cast a SimpleTag to the Tag return value of the Tag interface getParent(). We won’t go into how to access a Simple tag parent from a Classic child tag^[10], but all you need to know for the exam (and almost certainly real web app life) is that by using getParent(), a Classic tag can access Classic tag parents, and a Simple tag can access either a Classic or Simple parent.

Using the getParent() method, a Classic tag can access Classic tag parents, and a Simple tag can access either a Classic or Simple parent.

In a JSP

In the SimpleInner tag handler

In the ClassicParent tag handler

^[10] If you’re really curious, look at the TagAdapter class in the J2EE 1.4 API.