No Swing support at present. There is an issue filed, but it is in need of an implementer: https://github.com/konsoletyper/teavm/issues/406

I made a general guide for migrating from Swing to TeaVM here: https://frequal.com/TeaVM/migration/MigratingFromSwingToTeaV...

For a more specific example, I ported an open-source Java applet and described the process here: https://frequal.com/java/RestoringA19YearOldGameWithTeaVm.ht...