JavaFX
From APIDesign
JavaFX is new, modern UI toolkit for rendering Java UIs. The idea is tempting - instead of bloated AWT and Swing on top, one can use a completely independent UI and lightweight library instead. However, as usual when offering AlternativeBehaviour, the problem is co-existence - there a tons of Swing applications around and they need to migrate to JavaFX in an incremental fashion. Unless such migration is smooth, people will rather stick with what they have right now.