JSP vs Servlet: Which Is Right for You?

Jakarta Server Pages (JSPs) and Jakarta Servlet are types of Java technology used to create dynamic web applications. While these technologies are similar in their applications, each software has a distinct set of use cases and boundaries that differentiate it from the others. 

Understanding each type of application, along with its advantages and disadvantages, can help you make informed decisions when determining which will best suit your purposes, whether professionally or personally.

What is JSP?

Formerly known as Java Server Pages, Jakarta Server Pages (JSP) is a Java-based collection of technologies that allow you to write data-driven web content and insert Java into HTML pages. It combines writing markup with back-end interaction and creates JSP tags (either with HTML or XML) with JSP Actions and commands. When conceptualising JSP, you can consider it an extension of HTML programming. JSP allows you to modify HTML pages by embedding Java code, making it possible to create content that will change based on factors such as the date, time, and user input.

Once you translate this code into a Jakarta Servlet, you can execute it within the platform. You couldn’t do otherwise because HTTP servers cannot directly run Java web applications. Otherwise, you would have to forward Java applications to Java application servers. However, with JSPs, you can streamline the process and make it more straightforward.

Advantages of JSP

JSPs are translational between the web server and the Java scripts. JSP is considered an easy-to-learn application and is often the preferred technology when developing websites and other web applications. Typical advantages of JSP for web developers include these:

• Easy access to standard objects and actions when coding

• Code does not require translation between operating systems

• Uses a simplified, syntax-based scripting language

• Easily maintainable for future code use

• Ability to mix static HTML code with dynamic Servlet content

• Saves static and dynamic code in separate parts

• Allows tag-based programming

• Takes care of exception handling

• Easy to access Java components such as Java APIs, JNDI, JDBE, and EJB

• Allows for faster execution than many dynamic languages

• Uses JSP in Java EE

• Easy to use for non-Java programmers

Disadvantages of JSP

While many advantages of JSP exist, especially for non-Java programmers, you must recognise its disadvantages. Commonly considered disadvantages include the following:

• Speed is slow because of the need to translate JSP to Java code before compiling

• Can only deal with an HTTP request

• Difficult to debug and trace errors

• Lack of advanced features 

• Database connectivity can be an issue

• Limited to HTML format output

• Requires more storage on the server than on other pages

What is Java Servlet?

Java Servlet is a Java programming module for developing web-based applications and extending a web server's ability to host applications. It is a common alternative to Common Gateway Interface (CGI) programs and can be used to create platform-independent and component-based web applications. 

Java Servlet extends server capabilities through a request-response model. Web developers often use this technology to take advantage of Java's full features, as they can use Servlet to communicate with applets, databases, and other software using RMI and socket mechanisms. Servlets act as middlemen, receiving requests from applications and databases, processing them, and responding to them as HTTP and HTML pages. 

Advantages of Servlet

A web-based programmer may choose Servlet over JSP for several reasons. Servlet typically requires advanced Java knowledge and may be less suited for novice programmers. Consider the following advantages of Servlet:

• Enables rapid development through access to Java libraries

• Faster than CGI scripts or JSPs

• Able to use with many Java-based vendors

• Provides large sets of Java-compatible application programming interfaces (APIs) 

• Platform independence and easy development

• Easy coordination between multiple Servlets

• Web browser does not constrain usage

• Only one copy of Servlet loads into Java Virtual Machine (JVM)

Disadvantages of Servlet

When considering whether Servlet or JSP is right for you, consider the following disadvantages of Servlet:

• Requires advanced Java knowledge to use it effectively

• Implicit objects are not efficiently utilised ( must develop additional code)

• Exception handling needs to be specifically coded

• Challenging to write HTML code in Servlet programming

• Need Java Runtime Environment (JRE) to run Servlets

• Requests are threads, not processes

• Designing Servlets slows down the application

• Does not allow separate presentation logic from business logic (HTML versus Java code)

• Code is less readable than JSP code

• Does not allow tag-based programming

JSP vs Servlet: Things to consider

Web-based professionals must consider several key differences between JSP and Java Servlet when choosing the proper programming tools. For example, modifying JSP is more straightforward, while alterations in Servlet require reloading, recompiling, and restarting the server.

Other key differences to consider include:

Differences in programming language styles also relate to differences in function. JSP is slower than Servlet due to the need for translation and compilation before you can run it. JSP is also limited to HTTP protocol requests, while Servlet can receive protocol requests of all types. JSP can also use implicit objects and automate exception handling, while Servlet requires additional code and specification.

Another key difference is that JSP can separate business and presentation logic, while Servlet requires you to combine and present the logic. JSP relies on JavaBeans technology, allowing web pages to use JavaBeans. Servlet, on the other hand, uses specific APIs designed for use with the software. When executing programs, you can execute Servlet on web servers, while you must compile JSP in Servlet before implementing it.

How to determine which is right for you

Determining which platform is right for you will involve careful consideration of the advantages and disadvantages of each type of technology. Consider your expertise in computer programming, specifically Java, and how this may relate to your ability to use this software. Both programming languages are helpful tools for creating dynamic web content.

In general, JSP is best suited for developing view content and designing applications that rely more heavily on HTML code, using the presentation layer to help the application and user interact more effectively. Servlets are often used as controller classes and are more applicable when designing and developing a web application's business layer. The business layer is between the presentation and data access layers and involves business logic, security, and supporting site architecture.

Next steps

To learn more about each application and its uses, consider top courses on Coursera, such as Java Servlet Pages (JSPs) by LearnQuest. You can also broaden your knowledge and ability to work with Java in Java Programming and Software Engineering Fundamentals from Duke University.