ExpressJS vs Javalin: What are the differences?

Introduction: ExpressJS and Javalin are both popular frameworks used for building web applications. While ExpressJS is primarily used with Node.js, Javalin is based on Java. Despite their similarities in providing web application development capabilities, there are key differences between the two frameworks.

1. Programming Language: ExpressJS is a JavaScript framework that runs on Node.js, while Javalin is based on Java, making it suitable for developers who prefer working with Java.

2. Async Handling: ExpressJS requires developers to explicitly handle asynchronous operations using callbacks or promises, while Javalin simplifies this process by providing built-in support for handling async operations through coroutines.

3. Routing: ExpressJS uses a more traditional routing approach with route handlers defined using methods like app.get(), app.post(), etc., whereas Javalin uses a more concise approach with lambda expressions for defining routes.

4. Middleware: ExpressJS heavily relies on middleware functions for request processing, allowing developers to modify request and response objects, while Javalin emphasizes a more streamlined approach with middleware functions applied directly to routes.

5. Templating Engine: ExpressJS supports various templating engines like Pug, EJS, Handlebars, etc., for generating dynamic HTML content, whereas Javalin does not natively support templating engines, requiring developers to handle HTML generation separately.

6. Community Support: ExpressJS has a larger and more established community with a vast collection of plugins and resources available, making it easier for developers to find solutions and support, while Javalin, being relatively newer, may have a smaller community and fewer resources available.

In Summary, ExpressJS and Javalin differ in the programming language, async handling, routing, middleware usage, templating engine support, and community size.