Java Server Pages

<HTML>
<HEAD>
<% String title = "Hello World JSP"; %>
<TITLE><%= title %></TITLE>
</HEAD>
<BODY>
<H1><%= title %></H1>
</BODY>
</HTML>

download source, use right-click and "Save Target As..." to save with a .jsp extension.

online
The Java 2 Platform Specification
Books
Core JSP by Damon Hougland and Aaron Tavistock
Core Servlets and JavaServer Pages by Marty Hall