Difference Between Servlet and JSP (With Definitions)

By Indeed Editorial Team

Updated 2 September 2022 | Published 4 October 2021

Updated 2 September 2022

Published 4 October 2021

The Indeed Editorial Team comprises a diverse and talented team of writers, researchers and subject matter experts equipped with Indeed's data and insights to deliver useful tips to help guide your career journey.

Web applications are essential to the structure of the internet. You can develop a web application using web components like Servlet, JSP, etc. and other elements. The web components, like JSP and Servlet, generally execute in the web server and respond to the client request. In this article, we discuss the difference between Servlet and JSP and compare their advantages and disadvantages.

What Is The Difference Between JSP And Servlet?

A Servlet is a Java class that runs into a web container, and JSP is a text document that contains both static and dynamic data. Both Servlet and JSP have specific use cases.

Following are the basic differences between JSP and Servlet:

  • JSP is a server-side technology, whereas Servlet is a small Java class program that runs on the server.

  • JSP is easy to manage because in JSP separating business logic from presentation logic is easy, while in Servlet, business logic and presentation logic are together.

  • If you want to modify the JSP page, you do not need to recompile and redeploy the project. If you are going to change the UI of the application in Servlet, you need to update the code.

  • Coding of JSP is easier than Servlet because JSP is a tag-based approach, whereas Servlet is a Java code.

  • Servlet can accept any type of request, while JSP accepts only HTTP protocol requests.

  • JSP allows custom tags, but in Servlet, you can not build any custom tags.

  • In JSP, you can import packages anywhere in the file, whereas in Servlet, you need to import every package on top of the Servlet.

  • Session management is enabled by default in JSP, but in Servlet, users need to enable it separately.

  • In (MVC) Model View Controller architecture, JSP acts as a viewer while Servlet acts as a controller.

  • JSP is the preferred choice when there's less processing requirement. Servlet is the first choice when the processing and manipulation requirement is high.

What Is Servlet?

Servlet stands for server component, and it is a Java class program that runs on servers and extends servers' capabilities. It is a web component deployed on the server to create dynamic web pages. Servlet can take any kind of request and process to respond in the form of an HTML page.

Features Of Servlet

Some features of Servlet are as follows:

  • Used to create web applications

  • Acts as a communicator between client and server

  • An application programming interface (API) that provides many interfaces and classes, including documentations

  • Can generate a response to any kind of incoming request from the client

  • A web container (also called a Servlet container) required to deploy and run a Servlet

The life cycle of Servlet

The life cycle of a Servlet involves four stages, and the entire process runs in a Servlet container:

Stage 1: Loading and instantiation

The role of this stage is to load the Servlets. When a user requests to visit any URL, the browser generates an HTTP request for the URL. That HTTP request, received by the web server and forwarded to the Servlet container. The Servlet container maps and loads all the Servlets.

Stage 2: Initialisation/init() method

The purpose of this method is to initialise the Servlets. The container calls the init() method of the Servlet to notify that this Servlet instance is now is ready to pass into service. The container invokes this method only on the first request.

Stage 3: Request Processing/service() method

The purpose of this method is to process the client's request. The Servlet invokes the service() method to read the sent request data and formulate a response for the client. The Servlet persists in the container's space and can process more requests received from clients.

Stage 4: End/destroy() method

The container invokes the destroy() method to end the Servlet instance. The algorithms for this decision are specific to each container. This method runs only once during the life cycle of a Servlet and confirms the end of the Servlet instance. Finally, the Servlet's memory and its objects are garbage collected.

Why Use Servlet?

The performance speed of Servlet is faster, and professionals use it when they do not want to develop a separate process to handle every client's request. The common use case of Servlet is extending a web server by providing dynamic web content. Sometimes, people use Servlets if they do not need all the features of Java.

Related: 50 Essential Java Interview Programs

Advantages Of Servlet

Here are a few advantages of using Servlet:

  • Better performance: Because Servlet creates a thread for every client request and not a long process, that results in better performance.

  • Robust: Since JVM manages Servlet, the chances of memory leaks are rarest.

  • Competent: Memory is persistent so, the invocation is very efficient.

  • Elegant: The code is clean, object-oriented, modular, and intuitive.

  • Strong integration: Integrate well with the server to translate file paths, conduct logging, verify authorisation, and MIME type mapping.

  • Secure: Support safe programming because it uses java language.

Disadvantages Of Servlet

Here are some disadvantages of using Servlet:

  • Time-consuming: Modification in the Servlet file is time-consuming due to reloading, recompiling, and restarting the server.

  • Hefty: Writing HTML code in Servlet programming is challenging, and it makes Servlet looks bulky.

  • Difficult to understand: Writing complex business logic makes the application hard to comprehend.

  • Difficult to modify: Because HTML code and Java code are mixed, changes made in one code might alter the other, making modification difficult.

  • Requires broader knowledge: Servlet may not be suitable for non-java developers since it requires a profound knowledge of JSP Servlet.

  • Dependent: A java runtime environment requires on the server to run Servlet.

Related: Java vs Python: Key Differences and Similarities

What Is JSP?

Java Server Pages or JSP is a server-side technology. It is an extended version of Servlet technology developed by Sun Microsystems. In JSP, you write JAVA code inside HTML using JSP tags to create web pages. It gives more functionality than Servlet. A compatible web server with a Servlet container is necessary to execute JSP.

Features Of JSP

Some of the features of JSP are as follows:

  • Web-based technology

  • Used to create web applications

  • Helps to create dynamic and platform-independent web pages

  • Extended version of Servlet and allows more functionality

  • A component of Java EE, and used for the simplest to the most complex applications

  • Interacts smoothly with Java Servlets in a web container

  • Allows you to insert Java inside the HTML

The Life Cycle Of JSP

The life cycle of JSP starts with its creation, and the created Java file is translated into Servlet. Hereafter, the Servlet life cycle works until the cleanup.

Below are the steps in the JSP life cycle:

  1. Translation of JSP to Servlet: Here, in the first step, the .jsp file translates to _jsp.java.

  2. Compilation of JSP page: The compilation of the translated Java Servlet file (_jsp.java) occurs in a Servlet class file (_jsp.class).

  3. Classloading: Now, the compiled Servlet class loads into the container using classloader.

  4. Instantiation: In this step, the web container generates an instance of that Servlet class.

  5. Initialisation: The container invokes the _jspinit() method. _jspinit() method is invoked only once in a life cycle after Servlet instance generation.

  6. Request Processing: Now, the container invokes _jspservice() method to process the request. You cannot override this method.

  7. Destroy: _jspdestroy() method is used to destroy the Servlet instance from use. The container invokes the _jspDestroy() method to perform any required clean up. _jspdestroy() method is invoked only once. You can override this method.

Why Use JSP?

Compared to other dynamic languages, execution in JSP is considerably faster. JSP reduces the servers' effort to create processes because its compilation always occurs before the server processes. JSP is built over Servlets API and has access to all the Java APIs and other Java components.

Advantages Of JSP

Here are the advantages of using JSP:

  • Easy maintenance: JSP is easy to maintain since separating business logic with presentation logic is simple.

  • Servlet extension: Being the extension of Servlet technology, it can use all the features of Servlet.

  • Require less coding: It allows custom tags that reduces the code and makes coding flexible.

  • Fast development: There is no requirement to recompile and redeploy the project while modifying a JSP page.

  • Easy integration: Supports Java API's which can be easily integrated with the HTML code.

  • Easy modification: Changes can be done through the business logic page rather than changing every page that makes modification easy.

Related: Similarities and Differences Between C++ and Java

Disadvantages Of JSP

Here are some disadvantages of using JSP:

  • Hard to debug: Because JSP pages initially translate into Servlets before compilation, debugging or tracing errors is difficult.

  • Time-consuming: Because JSP pages are compiled on the server, they take more disc space and time to store JSP pages.

  • Fewer features: Since JSP output is HTML, it is not abundant in features.


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