Well this must have been around Java 1.2 or 1.4 IIRC, I'm not even sure if Hotspot was a a thing back then.

I just remember that GUI programming with Swing felt like molasses compared to native GUIs at that time (i.e. Win32/MFC, Cocoa, Motif).

But of course the cross-platform aspect was cool and since I did quite a bit with Solaris back then, Java got of course pushed a lot by Sun.