Introduction to JSP

JSP is Java's answer to the popular Microsoft's Active Server Pages (ASP). JSP, like ASP, provides a simplified and fast mean to generate dynamic web contents. It allows you to mix static HTML with dynamically generated HTML - in the way that the business logic and the presentation are well separated.

The advantages of JSP are:

1. Separation of static and dynamic contents: JSP enables the separation of static contents from dynamic contents.  The dynamic contents are generated via programming logic and inserted into the static template. This greatly simplifies the creation and maintenance of web contents.
2. Reuse of components and tag libraries: The dynamic contents can be provided by reusable components such as JavaBean, Enterprise JavaBean (EJB) and tag libraries - you do not have to re-inventing the wheels.
3. Java's power and portability

JSPs are Internally Compiled into Java Servlets

That is to say, anything that can be done using JSPs can also be accomplished using Java servlets. However, it is important to note that servlets and JSPs are complementary technologies, NOT replacement of each other. Servlet can be viewed as "HTML inside Java", which is better for implementing business logic - as it is Java dominant. JSP, on the other hand, is "Java inside HTML", which is superior for creating presentation - as it is HTML dominant. In a typical Model-View-Control (MVC) application, servlets are often used for the Controller (C), which involves complex programming logic. JSPs are often used for the View (V), which mainly deals with presentation. The Model (M) is usually implemented using JavaBean or EJB.