Java Swing turned out to be a failure because it didn't look native on any platform.
I would recommend something like Eto.Forms (https://github.com/picoe/Eto) which is an abstraction over native GUI toolkits (WPF, WinForms, GTK+, Cocoa)
My impression of Java UI components was that they looked boring and old-fashioned. It's a subjective judgement, but I guess others would have thought that way too. If Java Swing or other parts of the Java UI toolkit looked better than many native GUIs then there would have been more interest.
There has been a lot of interest. There are thousands upon thousands of big applications out there built on Swing, you just don't use them, because Java has never caught on in desktop consumer apps. But JetBrains' IDEs are based on Swing, as is NetBeans, and they look great.
I think looking great is entirely subjective.. I think that the JetBrains' IDEs look horrible... the skinning as it stands is inconsistent at best. They are cross platform.. but even looking like something built with bootstrap+fontawesome would look better. VS looks awesome (tends to run like ass though) by comparison.
Yup, it was different and it was worse. And full of bugs, particularly w.r.t. focus-handling, which even Sun's own (presumably correctly written) Swing applications were afflicted with.
I would recommend something like Eto.Forms (https://github.com/picoe/Eto) which is an abstraction over native GUI toolkits (WPF, WinForms, GTK+, Cocoa)
Works really well and mature.