Java Server Pages (JSP) is a technology for developing Webpages that supports dynamic content. This helps developers insert java code in HTML pages by making use of special JSP tags, most of which start with <% and end with %>.

A Java Server Pages component is a type of Java servlet that is designed to fulfill the role of a user interface for a Java web application. Web developers write JSPs as text files that combine HTML or XHTML code, XML elements, and embedded JSP actions and commands.

Using JSP, you can collect input from users through Webpage forms, present records from a database or another source, and create Webpages dynamically.

JSP tags can be used for a variety of purposes, such as retrieving information from a database or registering user preferences, accessing JavaBeans components, passing control between pages, and sharing information between requests, pages etc.

Why Use JSP?

Java Server Pages often serve the same purpose as programs implemented using the Common Gateway Interface (CGI). But JSP offers several advantages in comparison with the CGI.

Performance is significantly better because JSP allows embedding Dynamic Elements in HTML Pages itself instead of having separate CGI files.
JSP are always compiled before they are processed by the server unlike CGI/Perl which requires the server to load an interpreter and the target script each time the page is requested.
Java Server Pages are built on top of the Java Servlets API, so like Servlets, JSP also has access to all the powerful Enterprise Java APIs, including JDBC, JNDI, EJB, JAXP, etc.
JSP pages can be used in combination with servlets that handle the business logic, the model supported by Java servlet template engines.

Finally, JSP is an integral part of Java EE, a complete platform for enterprise class applications. This means that JSP can play a part in the simplest applications to the most complex and demanding.

Advantages of JSP

Following table lists out the other advantages of using JSP over other technologies −

Active Server Pages (ASP)

The advantages of JSP are twofold. First, the dynamic part is written in Java, not Visual Basic or other MS specific language, so it is more powerful and easier to use. Second, it is portable to other operating systems and non-Microsoft Web servers.

Pure Servlets

It is more convenient to write (and to modify!) regular HTML than to have plenty of println statements that generate the HTML.

Server-Side Includes (SSI)

SSI is really only intended for simple inclusions, not for “real” programs that use form data, make database connections, and the like.

JavaScript

JavaScript can generate HTML dynamically on the client but can hardly interact with the web server to perform complex tasks like database access and image processing etc.

Static HTML

Regular HTML, of course, cannot contain dynamic information.

JSP – Architecture

The web server needs a JSP engine, i.e., a container to process JSP pages. The JSP container is responsible for intercepting requests for JSP pages. This tutorial makes use of Apache which has built-in JSP container to support JSP pages development.

A JSP container works with the Web server to provide the runtime environment and other services a JSP needs. It knows how to understand the special elements that are part of JSPs.

Following diagram shows the position of JSP container and JSP files in a Web application.

jsp 2

JSP Processing

The following steps explain how the web server creates the Webpage using JSP −

As with a normal page, your browser sends an HTTP request to the web server.
The web server recognizes that the HTTP request is for a JSP page and forwards it to a JSP engine. This is done by using the URL or JSP page which ends with .jsp instead of .html.
The JSP engine loads the JSP page from disk and converts it into a servlet content. This conversion is very simple in which all template text is converted to println( ) statements and all JSP elements are converted to Java code. This code implements the corresponding dynamic behavior of the page.
The JSP engine compiles the servlet into an executable class and forwards the original request to a servlet engine.
A part of the web server called the servlet engine loads the Servlet class and executes it. During execution, the servlet produces an output in HTML format. The output is furthur passed on to the web server by the servlet engine inside an HTTP response.
The web server forwards the HTTP response to your browser in terms of static HTML content.
Finally, the web browser handles the dynamically-generated HTML page inside the HTTP response exactly as if it were a static page.

All the above-mentioned steps can be seen in the following diagram −

jsp 3

Typically, the JSP engine checks to see whether a servlet for a JSP file already exists and whether the modification date on the JSP is older than the servlet. If the JSP is older than its generated servlet, the JSP container assumes that the JSP hasn’t changed and that the generated servlet still matches the JSP’s contents. This makes the process more efficient than with the other scripting languages (such as PHP) and therefore faster.

So, in a way, a JSP page is really just another way to write a servlet without having to be a Java programming wiz. Except for the translation phase, a JSP page is handled exactly like a regular servlet.

So, this brings us to the end of blog. This Tecklearn ‘Overview of Java Server Pages and its Architecture’ blog helps you with commonly asked questions if you are looking out for a job in Java Programming. If you wish to learn JSP and build a career Java Programming domain, then check out our interactive, Java and JEE Training, that comes with 24*7 support to guide you throughout your learning period. Please find the link for course details:

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Java and JEE Certification Training is designed by professionals as per the industrial requirements and demands. This training encompasses comprehensive knowledge on basic and advanced concepts of core Java & J2EE along with popular frameworks like Hibernate, Spring & SOA. In this course, you will gain expertise in concepts like Java Array, Java OOPs, Java Function, Java Loops, Java Collections, Java Thread, Java Servlet, and Web Services using industry use-cases and this will help you to become a certified Java expert.

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What you will Learn in this Course?

Introduction to Java

Java Fundamentals
Introduction to Java Basics
Features of Java
Various components of Java language
Benefits of Java over other programming languages
Key Benefits of Java

Installation and IDE’s for Java Programming Language

Installation of Java
Setting up of Eclipse IDE
Components of Java Program
Editors and IDEs used for Java Programming
Writing a Simple Java Program

Data Handling and Functions

Data types, Operations, Compilation process, Class files, Loops, Conditions
Using Loop Constructs
Arrays- Single Dimensional and Multi-Dimensional
Functions
Functions with Arguments

OOPS in Java: Concept of Object Orientation

Object Oriented Programming in Java
Implement classes and objects in Java
Create Class Constructors
Overload Constructors
Inheritance
Inherit Classes and create sub-classes
Implement abstract classes and methods
Use static keyword
Implement Interfaces and use it

Polymorphism, Packages and String Handling

Concept of Static and Run time Polymorphism
Function Overloading
String Handling –String Class
Java Packages

Exception Handling and Multi-Threading

Exception handling
Various Types of Exception Handling
Introduction to multi-threading in Java
Extending the thread class
Synchronizing the thread

File Handling in Java

Input Output Streams
io Package
File Handling in Java

Java Collections

Wrapper Classes and Inner Classes: Integer, Character, Boolean, Float etc
Applet Programs: How to write UI programs with Applet, Java.lang, Java.io, Java.util
Collections: ArrayList, Vector, HashSet, TreeSet, HashMap, HashTable

Java Database Connectivity (JDBC)

Introduction to SQL: Connect, Insert, Update, Delete, Select
Introduction to JDBC and Architecture of JDBC
Insert/Update/Delete/Select Operations using JDBC
Batch Processing Transaction
Management: Commit and Rollback

Java Enterprise Edition – Servlets

Introduction to J2EE
Client Server architecture
URL, Port Number, Request, Response
Need for servlets
Servlet fundamentals
Setting up a web project in Eclipse
Configuring and running the web app with servlets
GET and POST request in web application with demo
Servlet lifecycle
Servlets Continued
Session tracking and filter
Forward and include Servlet request dispatchers

Java Server Pages (JSP)

Fundamentals of Java Server Page
Writing a code using JSP
The architecture of JSP
JSP Continued
JSP elements: Scriptlets, expressions, declaration
JSP standard actions
JSP directives
Introduction to JavaBeans
ServletConfig and ServletContext
Servlet Chaining
Cookies Management
Session Management

Hibernate

Introduction to Hibernate
Introduction to ORM
ORM features
Hibernate as an ORM framework
Hibernate features
Setting up a project with Hibernate framework
Basic APIs needed to do CRUD operations with Hibernate
Hibernate Architecture

POJO (Plain Old Java Object)

POJO (Plain Old Java Object)
Persistent Objects
Lifecycle of Persistent Object

Spring

Introduction to Spring
Spring Fundamentals
Advanced Spring

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