JavaServer Pages is an extension of the servlet component model that simplifies the process of generating HTML dynamically. JSP essentially allows you to incorporate Java directly into an HTML page as a scripting language. In J2EE, the Java code in a JSP page can access the JNDI ENC, just like the code in a servlet. In fact, JSP pages (text documents) are translated and compiled into Java servlets, which are then run in a web server just like any other servlet—some servers do the compilation automatically at runtime. You can also use JSP to generate XML documents dynamically.
You can learn more about JSP by reading JavaServer Pages™ by Hans Bergsten (O’Reilly).