The majority of your JSPs will probably not need to be changed. Both the IBM portlet API and the JSP 168 portlet API can leverage the Servlet 2.3 and JSP 1.2 specifications. You will need to change from the IBM JSP custom tags to the JSR custom tags.
The tag library needs to be changed to point to the JSR 168 tld and not the IBM tld.
For all JSP using portlet tag, change:
<%@ taglib uri="/WEB-INF/tld/portlet.tld" prefix="portletAPI" %>
<%@taglib uri="http://java.sun.com/portlet" prefix="portlet" %>
You can leave the prefix as portletAPI if you choose.
You will then need to define the tld in the web.xml. The tagib element needs to be placed after the error-page element. If you are not using an ...