For a fast, lightweight, Java-based front-end, try TeaVM and its Flavour toolkit:
It is easy to get started by using the maven archtetype, there's an tutorial in Java Magazine here:
https://blogs.oracle.com/javamagazine/post/java-in-the-brows...
With TeamVM and Flavour you get a full front-end SPA framework that lets you code business logic in Java, and pair that with HTML and CSS to make components.
To see what it can do, check out Wordii, a fast-paced 5-letter word game: * Wordii: https://frequal.com/wordii * Making Wordii using TeaVM and Flavour: https://frequal.com/java/MakingWordiiAPureJavaSpa.html