FreeMarker VS Vaadin

FreeMarker is a template engine, it allows to generate text output based on templates and dynamic data. It is similar to Mustache, Handlebars, Thymeleaf and other template engines. Templates are written in the FreeMarker Template Language (FTL) that supports conditional blocks, iterations, formatting, and many other capabilities.

Getting back to our two main technologies....we have implemented Keycloak as our Identification and Authorization Management system (IAM). However, as these things go, Keycloak has its own tech stack. One of the technologies, of course, is the language they used, which is Java. And being it is Java, they chose to use a templating engine called Freemarker.

The project I was working on was a website using Magnolia as their CMS. It uses the Freemarker templating engine under the hood. Essentially these are super-powered HTML files, which give you access to the CMS content. You can still use all of the HTML tags you want, including the

You can use Java for Backend and Frontend. A relative new kid on the block for Frontend is Qute. The general keyword you are searching for is Java Templating Engine. Specific examples would be Thymeleaf or FreeMarker. There are some framework, which offer a lot more than templating like Vaadin or Wicket. Some are just specifications like Jakarta Faces with some of their implementations MyFaces or Mojarra.

Keycloak uses FreeMaker to store and render templates. Read more about how Keycloak manages its themes in the official documentation.

For some component types, there is also the possibility to use a Freemarker template instead for more complex UI components. In this case, it will look like this:

From sing-up page to admin portal, you can customize pretty much any part of the UI using custom themes. Themes are developed using Freemarker Templates and it's all documented here.

But how do we explain the complexity of the current toolset? This is where the Law of the instrument kicks in: "If the only tool you have is a hammer, it is tempting to treat everything as if it were a nail.". Even if JavaScript was born in the web, JavaScript centered frameworks do not fit properly in the web. That is why we have huge bundles of JavaScript, that is why RSC are necessary (things like RSC were already a thing in Vaadin) and that is how JavaScript became the Birmingham screwdriver.

Off-topic but this blog is using https://vaadin.com, that's the first time I am seeing this framework being used!

But there are frameworks like GWT or Vaadin for Java, but none of them really took off afaik, I've never seen a job posting with either of these.

This small tutorial takes 15 minutes from the start to a working demo. We use Picovoice Porcupine Wake Word Engine to enable a Vaadin-based Java web application.

Are you a long-time Java developer using Spring-related tech stack? Vaadin can bring a fresh brief of the air into your daily development routines.

It’s been 7 years since we deployed our first Vaadin app for production. The whole process has been more than interesting. We developed the application according to an analysis (several modules for the agenda in the field of local government) based on a verbal assignment. The customer started testing on our server and after 2 months found only 3 bugs and requested 2 modifications beyond the original brief. Once implemented, we installed it at the customer’s site. The application started for the first time and is still running :-).

> Slightly off topic, but I found JSF the most productive out of any framework.

In my experience, it has been a horrible technology (even when combined with PrimeFaces) for complex functionality.

When you have a page that has a bunch of tabs, which have tables with custom action buttons, row editing, row expansion, as well as composite components, modal dialogs with other tables inside of those, various dropdowns or autocomplete components and so on, it will break in new ways all the time.

Sometimes the wrong row will be selected, even if you give every element a unique ID, sometimes updating a single table row after AJAX will be nigh impossible, other times the back end methods will be called with the wrong parameters, sometimes your composite components will act in weird ways (such as using the button to close a modal dialog doing nothing).

When used on something simple, it's an okay choice, but enterprise codebases that have been developed for years (not even a decade) across multiple versions will rot faster than just having a RESTful API and some separate SPA (that can be thrown out and rewritten altogether, if need be).

Another option in the space is Vaadin which feels okay, but has its own problems: https://vaadin.com/

Of course, my experiences are subjective and my own.

Did you find an excellent custom element that would make sense in your Vaadin Java web application? Maybe that is a web component that you previously published yourself in npmjs.com?