macwidget is free (LGPL) Swing UI toolkit
You can easily integrate macwdigets with your existing Swing Models.
[Thanks to Rene for the hint]
NEW: Online Workhop Effective WebApps without Frameworks is also coming to: MUC Airport.
Airport MUC workshops: Web (SPA, PWAs, Offline, Desktop, Mobile) Applications Essentials and Effective Web Applications. No migrations. #usetheplatform
Podcast: airhacks.fm and newsletter: airhacks.news
A book about rethinking Java EE Patterns