Workshop presented at PUCMM — November 2023. Co-presented with Freddy Peña.

Overview

In this workshop, we explored how the Java ecosystem has evolved to allow developers to build modern, highly interactive, and scalable web applications without the traditional complexity of managing separate frontend and backend stacks.

The focus was on Vaadin Flow, a framework that enables building web UIs 100% in Java, running on the server side while automatically handling the synchronization with the browser.

The Stack

We built a complete application from scratch using:

  • Java 17+ (OpenJDK)
  • Spring Boot 3 for the core application logic.
  • Vaadin Flow for the reactive web interface.
  • Jakarta Persistence (JPA) & MariaDB for data storage.
  • Spring Security for authentication and access control.
  • Docker & Traefik for local development and containerization.
  • OpenTofu & Ansible for automated deployment.

Key Modules

1. UI Development with Vaadin

We moved away from manual HTML/JS and used Vaadin’s component-based model. We explored:

  • Creating layouts with VerticalLayout and HorizontalLayout.
  • Data binding with the Binder API to connect Java Beans to forms.
  • Handling events and navigation using the @Route system.

2. Backend & Persistence

Integrated Spring Data JPA to manage our database entities. We emphasized:

  • Service layer abstraction.
  • Automatic database migrations with Flyway.
  • Secure data access patterns.

3. Security

Configuring Spring Security to protect views and data. Vaadin makes this seamless by providing annotations like @AnonymousAllowed or @RolesAllowed directly on the UI components.

4. Scalable Deployment

The final part of the workshop focused on taking the app to production:

  • Dockerization: Creating efficient multi-stage Docker builds.
  • Reverse Proxy: Using Traefik for automatic SSL and load balancing.
  • Automation: Using Ansible to provision and update the application servers.

Conclusion

Building web applications in Java doesn’t mean building “old” applications. With tools like Vaadin and Spring Boot, Java developers can achieve a development speed comparable to modern JS frameworks while maintaining the type safety and robustness of the JVM.

Resources