What is JSP?

JSP or Java Server Pages is a Java technology that allows developers to dynamically generate HTML, XML or some other type of web page. The technology allows Java code and certain pre-defined actions to be embedded into static content.

The JSP syntax adds additional XML tags, called JSP actions, to be used to invoke built-in functionality. Additionally, the technology allows for the creation of JSP tag libraries that act as extensions to the standard HTML or XML tags. Tag libraries provide a platform independent way of extending the capabilities of a web server.

JSPs are compiled into Servlets by a JSP compiler. A JSP compiler may generate a servlet in Java code that is then compiled by the Java compiler, or it may generate byte code for the servlet directly. In either case, it is helpful to understand how the JSP compiler transforms the page into a Java servlet.

JSP and Servlets
Architecturally speaking, JSP can be viewed as a high-level abstraction of servlets that is implemented as an extension of the Servlet 2.1 API.

About this Terminology
This terminology is from The Wikipedia which is published under the GNU Free Documentation License.