The JSP 1.1 specification builds on the JSP 1.0 specification.
JSP.E.4.1 Additions
Enabled the compilation of JSP pages into Servlet classes that can be transported from one JSP container to another.
Added a portable tag extension mechanism.
Flush is now an optional attribute of jsp:include , and a false value is valid and the default.
JSP.E.4.2 Changes
Use Servlet 2.2 instead of Servlet 2.1 (as clarified in Appendix JSP.B); Servlet 2.2 is still being finalized, but the specification is intended to be upward compatible.
jsp:plugin no longer can be implemented by just sending the contents of jsp:fallback to the client.