5 Java frameworks to build scalable web applications

Java is one of the most popular programming languages in 2019, a favorite of more than 7.6 million developers worldwide. Java is not usually associated with web development, but there are some excellent Java web frameworks available for web developers.

Java frameworks for web development simplify the build process by eliminating the need to write basic code like exception handling. As a result, business logic becomes the main focus for developers. 

If you have some experience with Java, you can get started quickly. In this article, we’ll review the 5 best Java web frameworks for 2019, and explain how to stack them.

1. Spring Framework

The Spring Framework is one of the most popular Java frameworks. It has a big ecosystem and a vast community around it. Spring allows you to develop enterprise-level Java web services, applications and microservices.

Developers use the Spring Framework for common programming tasks like data processing, security, and messaging. The modularity of the tools enables you to write clean and accessible code. The active Spring community provides help and answers question regarding how to do certain things or how things work.

Main Features:

• Excellent documentation and multiple tutorials.
• Huge ecosystem and community.
• Enhanced modularity to improve the readability of code.
• Simplified injection to test data through POJOs (Plain Old Java Objects) simplifies the codebase and makes it more flexible.

Downside: Spring is a complex Web Framework and if you are new to Java programming, then this probably isn’t the best choice for you. Spring requires a lot of prerequisite knowledge, and this makes the learning curve steep.

2. JavaServer Faces (JSF)

JavaServer Faces (JSF) is a framework for building Java web applications, developed by Oracle. It comes with in-depth, complex documentation

Developers use the JSF framework to build UIs of reusable components, manage the state of your components, connect components data sources, and bind user-generated events to event handlers on the server side.

Facelets is the default templating system of JSF, it was created especially for this project. Facelets allows you to use XML instead of Java for view handling. Other technologies such as XUL and plain Java allow you to create views. Web applications created with JSF are portable across different Java EE application servers as well.

Main Features:

• Oracle provides support for the code base.
• High-quality documentation.
• Reliable and stable framework.
• Official standard, part of the Java Community Process (JCP) program.
• Extensive set of tools and ecosystem. 

Downside: Non-JSF and JSF components can’t work together, as non-JSF components don’t acknowledge the stages of the JSF process.

3. Struts

Struts is an open-source MVC framework created by the Apache foundation. It’s a reliable platform with a large and supportive community. Java developers use Struts to create Java applications that are easy to maintain.

It is based on the MVC design fundamentals and has an architecture based on plugins. Struts plugins are basic JAR files that help extend the Struts framework to address different project needs. Some plugins such as the REST plugin, JSON plugin, and Config Browser Plugin are included in the MVC framework 

You can perform tasks that are not built into the framework by integrating with other Java frameworks. For example, for object-relational mapping you can use the dependency injection Spring plugin. Developers use to build the front-end applications using the different Struts client-side technologies, such as HTML with Angula or JavaServer Pages.

Main Feature:

• Exists since 2006, which makes it stable and free of bugs. 
• Works well with SOAP, REST, and AJAX.
• Allows modular development and integration with additional components.
• Supports templates and themes.
• Uses simple Plain Old Java Objects.

Downside: The Struts framework isn’t flexible, which means you need to get used to a specific set of rules regarding web application development and design. Developers tend to use a specific methodology they are already familiar with, and Struts requires them to use another set of rules.

4. Play!

The Play Framework is reactive and lets you develop scalable Java and Scala web applications. It addresses the problems of other Java frameworks, such as a steep learning curve, complicated architecture, and slow development cycles. 

Play improves developer productivity by offering features like hot code reloading, error messages in the browser and convention over configuration. Play provides a reactive system that follows modern web development principles like responsive images, resilient, elastic, and message-driven design.

Main Feature:

• Improves developer productivity.
• Quickly updates configuration changes, templates and java code.
• There are no no Java Enterprise Edition sessions, all connections are stateless.
• Can handle error in dev mode for runtime and compile errors.
• Easy to learn and get started.

Downside: The community isn’t as large as other Java frameworks and there aren’t as many Play plugins.

5. Google Web Toolkit (GWT)

GWT (Google Web Toolkit) is a Java framework for web developers from Google. GWT allows you to write client-side Java code and deploy it in the browser as JavaScript. Google Web Toolkit creates UIs of reusable components, similar to JavaServer Faces.

The GWT framework provides functionalities for standard web development work like bookmarking, history management, remote procedure calls, UI abstraction and more. In addition, you can create dynamic features such as drag and drop UIs using GWT’s pre-designed classes.

Main Feature:

• Supports responsive web applications with complex client-side design.
• Provides pre-designed panels and widgets and a set of CLI tools.
• Provides support for unit testing, internationalization and localization.
• Easy to learn, many online tutorials available.
• The code is divided into a number of JavaScript files that help the application load smoothly.
• Manages static resources in the code like images and CSS, which requires explicit declaration in the Java code.

Downside: Every client-side code change requires a new compilation. That makes GWT development slower, compared to other Java web frameworks. Developers are used to quickly refreshing the browser to see the changes.

Wrap Up

Web frameworks save a lot of development time by simplifying common web development tasks such as configuration changes. They also include features such as add-ons, plugins, integrations with third-party tools or pre-built UI elements.

Before choosing a framework, consider the nature of your application, the scale of the application, and your experience with using Web Frameworks and writing web applications in Java. Then, choose the framework that suits your needs.