OpenWorld provides an icon theme for GNOME or KDE.
It aims to follow FreeDesktop icon theme spec.
This icons collection was built gradually over couple of years. Icons were made for various purposes: StarOffice presentations, illustrations, design documents, OpenSolaris.org website, my blog etc.
Most of them were drawn while waiting in public places, like airports or bus stands or at home if dial-up connection goes down to trickling bytes. It is perhaps the most complete icon theme made on Java Desktop System. I haven't tested it on other Gnome or KDE desktops.
In the introduction about this collection I mentioned its design principle. It is done using SVG which is quite object oriented and one could easily reuse items from icon in another icon. Finally icons were rasterized to PNG using rsvg(1)
All icons are original and they do not intend to copy icons from any other operating system or icon theme. These are released under CDDL open source license. Feel free to copy the ideas for other icon themes!